fix(13-02): eliminate all ESLint violations — pnpm lint exits 0

- eslint.config.js: disable React Compiler rules (v7 flat.recommended enables
  them; codebase does not use the Compiler); add e2e/ to disableTypeChecked
  block; promote exhaustive-deps to error
- API broker: remove redundant as-casts (outboxWorker, poller, reminderScheduler,
  expand, sync, vevent, spike); add targeted ical.js no-unsafe-assignment/argument
  disables with justifying comments inside try blocks
- API routes/sse.ts: fix no-misused-promises on async writeSSE callback with
  void+IIFE+catch pattern
- API routes/lists.ts: let → const for updateValues
- API tests: remove unused imports (beforeEach, eq, vi); rename unused vars
  with _ prefix; remove unused lastActiveId assignment
- PWA components: void navigate() and void queryClient.invalidateQueries() on
  all fire-and-forget call sites; fix CalendarShell explicit-type-casts;
  Couldn't → HTML entity
- PWA test files: as unknown as Response for partial mock objects; string | null
  type annotation on mockLastSyncedUid; remove async from test callbacks without
  await; act(() => {}) not await act(async () => {}) for sync ops
- sw.ts: restructure Notification.data?.url access as let+if so disable
  comments land on the exact violation lines; void self.skipWaiting()

apps/api/src/broker/expand.ts

@@ -180,11 +180,13 @@ export function expandOccurrences(
   // --- 1. Parse VCALENDAR — return [] on malformed input (matches sync.ts pattern) ---
   let parsed: ReturnType<typeof ICAL.parse>
   try {
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment -- ical.js parse() returns 'any'; result is only passed to ICAL.Component which accepts it
     parsed = ICAL.parse(rawVevent)
   } catch {
     return []
   }
 
+  // eslint-disable-next-line @typescript-eslint/no-unsafe-argument -- ical.js parse() output is 'any'; ICAL.Component is the correct consumer of this value
   const comp = new ICAL.Component(parsed)
 
   // --- 2. Register VTIMEZONE components BEFORE constructing RecurExpansion (MANDATORY) ---
@@ -230,7 +232,7 @@ export function expandOccurrences(
       // Use ICAL.Event.endDate which derives end from DTEND, or DTSTART+DURATION, or sensible default.
       // Do NOT use getFirstPropertyValue('dtend') directly — events with only DURATION set return null,
       // producing zero-duration occurrences (BUG 1).
-      let occEnd: ICAL.Time = (event.endDate ?? dtstart) as ICAL.Time
+      let occEnd: ICAL.Time = event.endDate ?? dtstart
 
       // Positive-duration guard: ensure timed events have non-zero height in Schedule-X.
       if (!allDay && occEnd.compare(dtstart) <= 0) {

apps/api/src/broker/outboxWorker.ts

@@ -372,7 +372,7 @@ async function dispatchRow(row: OutboxRow): Promise<DispatchResult> {
             rruleFromPayload,
             fields.recurrenceUntil,
             fields.recurrenceCount,
-            fields.allDay as boolean,
+            fields.allDay,
           )
         : undefined
     } else if (preservedRrule) {
@@ -383,7 +383,7 @@ async function dispatchRow(row: OutboxRow): Promise<DispatchResult> {
           strippedPreset,
           fields.recurrenceUntil,
           fields.recurrenceCount,
-          fields.allDay as boolean,
+          fields.allDay,
         )
       } else {
         finalRruleString = preservedRrule
@@ -394,12 +394,12 @@ async function dispatchRow(row: OutboxRow): Promise<DispatchResult> {
 
     const { icsString } = buildVeventString({
       uid: row.uid,
-      summary: fields.title as string,
+      summary: fields.title,
-      allDay: fields.allDay as boolean,
+      allDay: fields.allDay,
-      dtstart: fields.allDay ? (fields.start as string) : new Date(fields.start as string),
+      dtstart: fields.allDay ? fields.start : new Date(fields.start),
-      dtend: fields.allDay ? (fields.end as string) : new Date(fields.end as string),
+      dtend: fields.allDay ? fields.end : new Date(fields.end),
-      location: fields.location as string | undefined,
+      location: fields.location,
-      description: fields.description as string | undefined,
+      description: fields.description,
       rruleString: finalRruleString,
     })
 
@@ -463,7 +463,7 @@ async function dispatchRow(row: OutboxRow): Promise<DispatchResult> {
             rruleFromPayload,
             fields.recurrenceUntil,
             fields.recurrenceCount,
-            fields.allDay as boolean,
+            fields.allDay,
           )
         : undefined
     } else if (preservedRrule) {
@@ -474,7 +474,7 @@ async function dispatchRow(row: OutboxRow): Promise<DispatchResult> {
           strippedPreset,
           fields.recurrenceUntil,
           fields.recurrenceCount,
-          fields.allDay as boolean,
+          fields.allDay,
         )
       } else {
         finalRruleString = preservedRrule
@@ -485,12 +485,12 @@ async function dispatchRow(row: OutboxRow): Promise<DispatchResult> {
 
     const { icsString } = buildVeventString({
       uid: row.uid,
-      summary: fields.title as string,
+      summary: fields.title,
-      allDay: fields.allDay as boolean,
+      allDay: fields.allDay,
-      dtstart: fields.allDay ? (fields.start as string) : new Date(fields.start as string),
+      dtstart: fields.allDay ? fields.start : new Date(fields.start),
-      dtend: fields.allDay ? (fields.end as string) : new Date(fields.end as string),
+      dtend: fields.allDay ? fields.end : new Date(fields.end),
-      location: fields.location as string | undefined,
+      location: fields.location,
-      description: fields.description as string | undefined,
+      description: fields.description,
       rruleString: finalRruleString,
     })
     // Build a minimal DAVCalendar for the write wrapper (only url is needed)

apps/api/src/broker/poller.ts

@@ -56,7 +56,7 @@ export async function runPoll(): Promise<void> {
 
         // ctag/syncToken: defensive null handling (Pitfall #6)
         const knownCtag = stored?.ctag ?? null
-        const currentCtag = (davCal.ctag ?? davCal.syncToken ?? null) as string | null
+        const currentCtag = davCal.ctag ?? davCal.syncToken ?? null
 
         // Skip if ctag is present on both sides and unchanged
         if (currentCtag !== null && currentCtag === knownCtag) {

apps/api/src/broker/reminderScheduler.ts

@@ -129,7 +129,7 @@ export async function runReminderCheck(now = new Date()): Promise<void> {
     if (row.subId != null) {
       byUid.get(row.uid)!.subs.push({
         id: row.subId,
-        userId: row.subUserId!,
+        userId: row.subUserId,
         endpoint: row.subEndpoint,
         p256dh: row.subP256dh,
         auth: row.subAuth,

apps/api/src/broker/spike.ts

@@ -50,7 +50,9 @@ async function main() {
   for (const cal of calendars) {
     console.log('---')
     console.log(`  url:         ${cal.url}`)
-    console.log(`  displayName: ${cal.displayName ?? '(none)'}`)
+    // displayName may be a string or a Record (language-tagged value) per CalDAV spec
+    const displayName = typeof cal.displayName === 'string' ? cal.displayName : JSON.stringify(cal.displayName ?? '(none)')
+    console.log(`  displayName: ${displayName}`)
     // ctag/syncToken: Fastmail may return either field (Pitfall #6)
     console.log(`  ctag:        ${(cal as { ctag?: string }).ctag ?? '(not returned)'}`)
     console.log(`  syncToken:   ${(cal as { syncToken?: string }).syncToken ?? '(not returned)'}`)

apps/api/src/broker/sync.ts

@@ -86,12 +86,14 @@ export async function syncCalendar(
 
     let parsed: ReturnType<typeof ICAL.parse>
     try {
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment -- ical.js parse() returns 'any'; result is only passed to ICAL.Component which accepts it
       parsed = ICAL.parse(obj.data as string)
     } catch {
       // Malformed VCALENDAR — skip but do not crash the sync
       continue
     }
 
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-argument -- ical.js parse() output is 'any'; ICAL.Component is the correct consumer of this value
     const comp = new ICAL.Component(parsed)
     const vevent = comp.getFirstSubcomponent('vevent')
     if (!vevent) continue
@@ -198,13 +200,14 @@ export async function syncCalendar(
         if ((oldRow.allDay ? true : false) !== allDay) changedFields.push('allDay')
 
         // Compare title (SUMMARY)
-        const oldTitle = (oldRow.title ?? null) as string | null
+        const oldTitle = oldRow.title ?? null
         if (oldTitle !== titleValue) changedFields.push('title')
 
         // Compare location — extract from old rawVevent for comparison
         let oldLocation: string | null = null
         if (oldRow.rawVevent) {
           try {
+            // eslint-disable-next-line @typescript-eslint/no-unsafe-argument -- ical.js parse() returns 'any'; ICAL.Component is the correct consumer of this value
             const oldComp = new ICAL.Component(ICAL.parse(oldRow.rawVevent))
             const oldVevent = oldComp.getFirstSubcomponent('vevent')
             if (oldVevent) {

apps/api/src/broker/vevent.ts

@@ -63,10 +63,12 @@ export const RRULE_PRESETS: Record<string, string> = {
 export function extractRruleString(rawVevent: string): string | undefined {
   let parsed: ReturnType<typeof ICAL.parse>
   try {
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment -- ical.js parse() returns 'any'; result is only passed to ICAL.Component which accepts it
     parsed = ICAL.parse(rawVevent)
   } catch {
     return undefined
   }
+  // eslint-disable-next-line @typescript-eslint/no-unsafe-argument -- ical.js parse() output is 'any'; ICAL.Component is the correct consumer of this value
   const comp = new ICAL.Component(parsed)
   const vevent = comp.getFirstSubcomponent('vevent')
   if (!vevent) return undefined

apps/api/src/routes/lists.ts

@@ -601,7 +601,7 @@ listItemsRouter.patch('/:itemId', zValidator('json', patchItemSchema), async (c)
     }
 
     // Build the update payload — single-field write with updatedAt=NOW()
-    let updateValues: {
+    const updateValues: {
       checked?: boolean
       text?: string
       rank?: string

apps/api/src/routes/sse.ts

@@ -93,13 +93,19 @@ sseRouter.get('/lists', async (c) => {
 
     // Subscribe to each accessible list's channel (D-04 — scoped, not global)
     for (const listId of accessibleListIds) {
-      const unsub = subscribeListEvents(listId, async (event) => {
+      const unsub = subscribeListEvents(listId, (event) => {
+        // The handler signature is void-returning; wrap the async write in void+catch.
+        // writeSSE errors are non-fatal — the SSE loop detects stream.aborted and cleans up.
+        void (async () => {
           if (stream.aborted) return
           await stream.writeSSE({
             data: JSON.stringify(event),
             event: event.type,
             id: `${listId}-${Date.now()}`,
           })
+        })().catch((err: unknown) => {
+          console.error('[sse] writeSSE error:', err)
+        })
       })
       unsubscribers.push(unsub)
     }

apps/api/tests/auth/devBypass.test.ts

@@ -7,7 +7,7 @@
  *  3. NODE_ENV!='production' + DEV_AUTH_BYPASS='true' → DEV_USER injected into context
  */
 
-import { describe, it, expect, beforeEach, afterEach } from 'vitest'
+import { describe, it, expect, afterEach } from 'vitest'
 import { Hono } from 'hono'
 
 // We import after env manipulation since devAuthBypass() reads env vars at call time.

apps/api/tests/broker/poller.test.ts

@@ -32,7 +32,7 @@ const mockCredentialsSelectResult: Array<{
 
 // Each call to db.select() needs to return different chains
 // We use a call counter to decide which data to return
-let selectCallCount = 0
+let _callCount = 0
 
 const mockSelectLimit = vi.fn()
 const mockSelectWhere = vi.fn().mockReturnValue({ limit: mockSelectLimit })
@@ -44,7 +44,7 @@ mockSelectFrom.mockImplementation(() => ({
   where: mockSelectWhere,
   // Support both: direct await (no where) and .where().limit()
   then: (resolve: (v: typeof mockCredentialsSelectResult) => void) => {
-    selectCallCount++
+    _callCount++
     resolve(mockCredentialsSelectResult)
     return Promise.resolve(mockCredentialsSelectResult)
   },
@@ -71,7 +71,7 @@ vi.mock('../../src/broker/client.js', () => ({
 describe('broker poller — runPoll', () => {
   beforeEach(() => {
     vi.clearAllMocks()
-    selectCallCount = 0
+    _callCount = 0
 
     // Reset implementations
     mockSyncCalendar.mockResolvedValue(undefined)

apps/api/tests/routes/events.test.ts

@@ -518,7 +518,7 @@ describe('GET /api/events/sync-status', () => {
     const mockOrderBy = vi.fn().mockImplementation(() => Promise.resolve(mockDbRows))
     const mockLimit = vi.fn().mockReturnValue(mockOrderBy)
     const mockSimpleWhere = vi.fn().mockReturnValue({ limit: mockLimit })
-    const mockOrderByDirect = vi.fn().mockImplementation(() => Promise.resolve(mockDbRows))
+    const _mockOrderByDirect = vi.fn().mockImplementation(() => Promise.resolve(mockDbRows))
     // Some implementations use .where().orderBy() or just .where()
     mockSimpleWhere.mockReturnValue({ limit: mockLimit, orderBy: vi.fn().mockReturnValue({ limit: vi.fn().mockResolvedValue(mockDbRows) }) })
     mockFromFn.mockReturnValue({ where: mockSimpleWhere })

apps/api/tests/routes/lists.test.ts

@@ -510,7 +510,6 @@ async function seedItem(
   rank: string,
   checked = false,
 ): Promise<number> {
-  const { eq } = await import('drizzle-orm')
   const [result] = await db.insert(listItems).values({ listId, text, rank, checked }).$returningId()
   return result.id
 }
@@ -646,7 +645,7 @@ describe('PATCH /api/list-items/:id — per-field LWW (D-08)', () => {
     const listId = await seedList(ownerId, 'Uncheck Rank', false)
     // Two active items
     await seedItem(listId, 'alpha', 'a0')
-    const lastActiveId = await seedItem(listId, 'beta', 'a1')
+    await seedItem(listId, 'beta', 'a1')
     // One checked item (to uncheck)
     const checkedItemId = await seedItem(listId, 'checked-one', 'Zz', true)
 
@@ -1055,8 +1054,8 @@ describe('PATCH /api/list-items/:id { position } — reorder ordering (LIST-03,
     const ownerId = await seedUser('reorder-lww')
     currentDevUserId = ownerId
     const listId = await seedList(ownerId, 'Reorder LWW', false)
-    const id1 = await seedItem(listId, 'alpha', 'a0')
+    const _id1 = await seedItem(listId, 'alpha', 'a0')
-    const id2 = await seedItem(listId, 'beta', 'a1')
+    const _id2 = await seedItem(listId, 'beta', 'a1')
     const id3 = await seedItem(listId, 'gamma', 'a2')
 
     const app = await getApp()

apps/pwa/src/api/client.test.ts

@@ -175,8 +175,8 @@ describe('createEvent', () => {
     const mockFetch = vi.mocked(fetch)
     mockFetch.mockResolvedValueOnce({
       ok: true,
-      json: async () => ({ uid: 'test-uid-123' }),
+      json: () => ({ uid: 'test-uid-123' }),
-    } as Response)
+    } as unknown as Response)
 
     const { createEvent } = await import('./client.js')
     const payload = {
@@ -193,6 +193,7 @@ describe('createEvent', () => {
       expect.objectContaining({
         method: 'POST',
         credentials: 'include',
+        // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment -- expect.objectContaining returns 'any' (Vitest asymmetric matcher); safe in assertion context
         headers: expect.objectContaining({ 'Content-Type': 'application/json' }),
       }),
     )
@@ -201,8 +202,8 @@ describe('createEvent', () => {
   it('returns { uid } from 202 response', async () => {
     vi.mocked(fetch).mockResolvedValueOnce({
       ok: true,
-      json: async () => ({ uid: 'returned-uid-456' }),
+      json: () => ({ uid: 'returned-uid-456' }),
-    } as Response)
+    } as unknown as Response)
 
     const { createEvent } = await import('./client.js')
     const result = await createEvent({
@@ -220,8 +221,8 @@ describe('createEvent', () => {
     vi.mocked(fetch).mockResolvedValueOnce({
       ok: false,
       status: 400,
-      json: async () => ({ error: 'Bad Request' }),
+      json: () => ({ error: 'Bad Request' }),
-    } as Response)
+    } as unknown as Response)
 
     const { createEvent } = await import('./client.js')
     await expect(
@@ -250,8 +251,8 @@ describe('updateEvent', () => {
     const mockFetch = vi.mocked(fetch)
     mockFetch.mockResolvedValueOnce({
       ok: true,
-      json: async () => ({ uid: 'edit-uid-789' }),
+      json: () => ({ uid: 'edit-uid-789' }),
-    } as Response)
+    } as unknown as Response)
 
     const { updateEvent } = await import('./client.js')
     await updateEvent('edit-uid-789', {
@@ -274,8 +275,8 @@ describe('updateEvent', () => {
   it('returns { uid } on success', async () => {
     vi.mocked(fetch).mockResolvedValueOnce({
       ok: true,
-      json: async () => ({ uid: 'patched-uid' }),
+      json: () => ({ uid: 'patched-uid' }),
-    } as Response)
+    } as unknown as Response)
 
     const { updateEvent } = await import('./client.js')
     const result = await updateEvent('some-uid', {
@@ -303,12 +304,12 @@ describe('fetchWritableCalendars', () => {
   it('GETs /api/events/writable-calendars with credentials:include', async () => {
     vi.mocked(fetch).mockResolvedValueOnce({
       ok: true,
-      json: async () => ({
+      json: () => ({
         calendars: [
           { url: 'https://caldav.fastmail.com/cal1', displayName: 'My Calendar', color: '#4A90D9', isShared: false },
         ],
       }),
-    } as Response)
+    } as unknown as Response)
 
     const { fetchWritableCalendars } = await import('./client.js')
     await fetchWritableCalendars()
@@ -326,8 +327,8 @@ describe('fetchWritableCalendars', () => {
     ]
     vi.mocked(fetch).mockResolvedValueOnce({
       ok: true,
-      json: async () => ({ calendars: mockCalendars }),
+      json: () => ({ calendars: mockCalendars }),
-    } as Response)
+    } as unknown as Response)
 
     const { fetchWritableCalendars } = await import('./client.js')
     const result = await fetchWritableCalendars()
@@ -340,7 +341,7 @@ describe('fetchWritableCalendars', () => {
     vi.mocked(fetch).mockResolvedValueOnce({
       ok: false,
       status: 401,
-    } as Response)
+    } as unknown as Response)
 
     const { fetchWritableCalendars } = await import('./client.js')
     await expect(fetchWritableCalendars()).rejects.toThrow()
@@ -361,8 +362,8 @@ describe('deleteEvent', () => {
     const mockFetch = vi.mocked(fetch)
     mockFetch.mockResolvedValueOnce({
       ok: true,
-      json: async () => ({}),
+      json: () => ({}),
-    } as Response)
+    } as unknown as Response)
 
     const { deleteEvent } = await import('./client.js')
     await deleteEvent('uid-to-delete')
@@ -379,8 +380,8 @@ describe('deleteEvent', () => {
   it('resolves void on success (204/202)', async () => {
     vi.mocked(fetch).mockResolvedValueOnce({
       ok: true,
-      json: async () => ({}),
+      json: () => ({}),
-    } as Response)
+    } as unknown as Response)
 
     const { deleteEvent } = await import('./client.js')
     const result = await deleteEvent('uid-abc')
@@ -391,7 +392,7 @@ describe('deleteEvent', () => {
     vi.mocked(fetch).mockResolvedValueOnce({
       ok: false,
       status: 404,
-    } as Response)
+    } as unknown as Response)
 
     const { deleteEvent } = await import('./client.js')
     await expect(deleteEvent('missing-uid')).rejects.toThrow()
@@ -411,8 +412,8 @@ describe('fetchSyncStatus', () => {
   it('GETs /api/events/sync-status?uid= with credentials:include', async () => {
     vi.mocked(fetch).mockResolvedValueOnce({
       ok: true,
-      json: async () => ({ uid: 'my-uid', status: 'pending' }),
+      json: () => ({ uid: 'my-uid', status: 'pending' }),
-    } as Response)
+    } as unknown as Response)
 
     const { fetchSyncStatus } = await import('./client.js')
     await fetchSyncStatus('my-uid')
@@ -426,8 +427,8 @@ describe('fetchSyncStatus', () => {
   it('returns SyncStatus object with uid and status', async () => {
     vi.mocked(fetch).mockResolvedValueOnce({
       ok: true,
-      json: async () => ({ uid: 'test-uid', status: 'done' }),
+      json: () => ({ uid: 'test-uid', status: 'done' }),
-    } as Response)
+    } as unknown as Response)
 
     const { fetchSyncStatus } = await import('./client.js')
     const result = await fetchSyncStatus('test-uid')
@@ -437,8 +438,8 @@ describe('fetchSyncStatus', () => {
   it('returns SyncStatus with error field for failed status', async () => {
     vi.mocked(fetch).mockResolvedValueOnce({
       ok: true,
-      json: async () => ({ uid: 'fail-uid', status: 'failed', error: '412 Conflict' }),
+      json: () => ({ uid: 'fail-uid', status: 'failed', error: '412 Conflict' }),
-    } as Response)
+    } as unknown as Response)
 
     const { fetchSyncStatus } = await import('./client.js')
     const result = await fetchSyncStatus('fail-uid')
@@ -449,7 +450,7 @@ describe('fetchSyncStatus', () => {
     vi.mocked(fetch).mockResolvedValueOnce({
       ok: false,
       status: 500,
-    } as Response)
+    } as unknown as Response)
 
     const { fetchSyncStatus } = await import('./client.js')
     await expect(fetchSyncStatus('any-uid')).rejects.toThrow()
@@ -471,8 +472,8 @@ describe('fetchMe', () => {
       ok: true,
       type: 'basic',
       status: 200,
-      json: async () => ({ user: { id: 2, displayName: 'Me', color: '#E8734A' } }),
+      json: () => ({ user: { id: 2, displayName: 'Me', color: '#E8734A' } }),
-    } as Response)
+    } as unknown as Response)
 
     const { fetchMe } = await import('./client.js')
     await fetchMe()
@@ -488,8 +489,8 @@ describe('fetchMe', () => {
       ok: true,
       type: 'basic',
       status: 200,
-      json: async () => ({ user: { id: 2, displayName: 'Me', color: '#E8734A' } }),
+      json: () => ({ user: { id: 2, displayName: 'Me', color: '#E8734A' } }),
-    } as Response)
+    } as unknown as Response)
 
     const { fetchMe } = await import('./client.js')
     const result = await fetchMe()
@@ -503,7 +504,7 @@ describe('fetchMe', () => {
       ok: false,
       type: 'opaqueredirect',
       status: 0,
-      json: async () => {
+      json: () => {
         throw new Error('body not accessible on opaqueredirect')
       },
     } as unknown as Response)
@@ -517,7 +518,7 @@ describe('fetchMe', () => {
       ok: false,
       type: 'basic',
       status: 401,
-    } as Response)
+    } as unknown as Response)
 
     const { fetchMe } = await import('./client.js')
     await expect(fetchMe()).rejects.toThrow(/authentication required/i)

apps/pwa/src/components/AppNav.test.tsx

@@ -12,7 +12,7 @@
 
 import React from 'react'
 import { describe, it, expect, vi, beforeEach } from 'vitest'
-import { render, screen, waitFor } from '@testing-library/react'
+import { render, screen } from '@testing-library/react'
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
 
 // ── Module mocks ────────────────────────────────────────────────────────────

apps/pwa/src/components/CalendarShell.tsx

@@ -156,7 +156,7 @@ export function CalendarShell() {
   // IANATimezone (the config's timezone type) is declared but not exported by @schedule-x/calendar,
   // so derive it from useCalendarApp's config parameter rather than importing it.
   type SxTimeZone = NonNullable<Parameters<typeof useCalendarApp>[0]['timezone']>
-  const displayTimeZone = Intl.DateTimeFormat().resolvedOptions().timeZone as SxTimeZone
+  const displayTimeZone: SxTimeZone = Intl.DateTimeFormat().resolvedOptions().timeZone
 
   // useCalendarApp — config is stable; plugins passed as second argument
   const calendar = useCalendarApp(
@@ -169,7 +169,7 @@ export function CalendarShell() {
       ],
       defaultView,
       timezone: displayTimeZone,
-      firstDayOfWeek: SX_FIRST_DAY_OF_WEEK as 7,
+      firstDayOfWeek: SX_FIRST_DAY_OF_WEEK,
       calendars: calendarsConfig,
       callbacks: {
         onRangeUpdate(range) {
@@ -197,7 +197,7 @@ export function CalendarShell() {
   useEffect(() => {
     if (!eventsQuery.data) return
     const sxEvents = hydrateEvents(eventsQuery.data.occurrences)
-    eventsService.set(sxEvents as Parameters<typeof eventsService.set>[0])
+    eventsService.set(sxEvents)
   }, [eventsQuery.data, eventsService])
 
   // Auth redirect — one-shot full-page nav to /api/login when /api/me fails.
@@ -351,7 +351,7 @@ export function CalendarShell() {
                   color: 'var(--color-text-primary)',
                 }}
               >
-                Couldn't load events
+                Couldn&apos;t load events
               </h2>
               <p
                 style={{
@@ -363,7 +363,7 @@ export function CalendarShell() {
                 Check your connection and try again.
               </p>
               <button
-                onClick={() => queryClient.refetchQueries({ queryKey: ['events'] })}
+                onClick={() => { void queryClient.refetchQueries({ queryKey: ['events'] }) }}
                 style={{
                   background: 'var(--color-surface-dim)',
                   border: '1px solid var(--color-border)',

apps/pwa/src/components/CreateListSheet.tsx

@@ -22,7 +22,7 @@
 import { useEffect, useRef, useState } from 'react'
 import { useMutation, useQueryClient } from '@tanstack/react-query'
 import { createList } from '../api/listsClient.js'
-import type { List, ListsResponse } from '../api/listsClient.js'
+import type { ListsResponse } from '../api/listsClient.js'
 import { useListsStore } from '../store/listsStore.js'
 
 export function CreateListSheet() {
@@ -82,7 +82,7 @@ export function CreateListSheet() {
             ownerId: 0, // unknown until response
             activeCount: 0,
             doneCount: 0,
-          } as List,
+          },
         ],
       }))
       return { previous }
@@ -94,8 +94,8 @@ export function CreateListSheet() {
       }
     },
     onSettled: () => {
-      // Always invalidate to get canonical server state
+      // Always invalidate to get canonical server state; fire-and-forget (React Query handles cache update)
-      queryClient.invalidateQueries({ queryKey: ['lists'] })
+      void queryClient.invalidateQueries({ queryKey: ['lists'] })
     },
     onSuccess: () => {
       handleClose()

apps/pwa/src/components/DeleteConfirmationDialog.test.tsx

@@ -33,7 +33,7 @@ const {
   mockSetLastSyncedUid: vi.fn(),
   mockSetOpenEventId: vi.fn(),
   mockDeleteDialogOpen: { value: true },
-  mockDeleteDialogUid: { value: 'event-uid-to-delete' as string | null },
+  mockDeleteDialogUid: { value: 'event-uid-to-delete' },
 }))
 
 vi.mock('../store/calendarStore.js', () => ({

apps/pwa/src/components/EventForm.test.tsx

@@ -332,7 +332,7 @@ describe('EventForm', () => {
     const tomorrow = new Date(today)
     tomorrow.setDate(today.getDate() + 1)
     const todayStr = today.toISOString().slice(0, 10)
-    const yesterdayStr = new Date(today.setDate(today.getDate() - 1)).toISOString().slice(0, 10)
+    const _yesterdayStr = new Date(today.setDate(today.getDate() - 1)).toISOString().slice(0, 10)
 
     if (dateInputs.length >= 2) {
       fireEvent.change(dateInputs[0], { target: { value: todayStr } })
@@ -462,7 +462,7 @@ describe('EventForm', () => {
       eventOccurrence: EDIT_OCCURRENCE,
     })
 
-    const titleInput = screen.getByPlaceholderText('Event title') as HTMLInputElement
+    const titleInput = screen.getByPlaceholderText<HTMLInputElement>('Event title')
     expect(titleInput.value).toBe('Existing Meeting')
   })
 })
@@ -560,7 +560,7 @@ describe('EventForm — Plan 03-12 gap closures', () => {
     )
 
     // Title should be empty (occurrence not yet in cache)
-    const titleInput = screen.getByPlaceholderText('Event title') as HTMLInputElement
+    const titleInput = screen.getByPlaceholderText<HTMLInputElement>('Event title')
     expect(titleInput.value).toBe('')
 
     // Phase 2: occurrence arrives in cache (simulating TanStack Query resolving)
@@ -576,7 +576,7 @@ describe('EventForm — Plan 03-12 gap closures', () => {
     // WR-03 fix: the reset effect must re-run because occurrence changed,
     // so the title should now be populated
     await waitFor(() => {
-      const titleInputAfter = screen.getByPlaceholderText('Event title') as HTMLInputElement
+      const titleInputAfter = screen.getByPlaceholderText<HTMLInputElement>('Event title')
       expect(titleInputAfter.value).toBe('Late-Arriving Meeting')
     })
   })
@@ -676,7 +676,7 @@ describe('EventForm — Plan 03-12 gap closures', () => {
 
   it('IN-03: todayIso is exported from calendarStore (single source of truth)', async () => {
     // Use importActual to bypass the vi.mock() and test the real module export
-    const actualModule = await vi.importActual('../store/calendarStore.js') as Record<string, unknown>
+    const actualModule = await vi.importActual('../store/calendarStore.js')
     expect(typeof actualModule.todayIso).toBe('function')
     const result = (actualModule.todayIso as () => string)()
     // Should return a YYYY-MM-DD string
@@ -950,9 +950,11 @@ describe('EventForm — Plan 06-06 end-tracking + recurrence-bound', () => {
 
     await waitFor(() => {
       expect(mockCreateEvent).toHaveBeenCalledWith(
+        // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment -- expect.anything() returns 'any' (Vitest asymmetric matcher); safe in assertion context
         expect.not.objectContaining({ recurrenceUntil: expect.anything() }),
       )
       expect(mockCreateEvent).toHaveBeenCalledWith(
+        // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment -- expect.anything() returns 'any' (Vitest asymmetric matcher); safe in assertion context
         expect.not.objectContaining({ recurrenceCount: expect.anything() }),
       )
     })

apps/pwa/src/components/EventForm.tsx

@@ -271,7 +271,7 @@ export function EventForm() {
       // read it if a future API version adds it, and default to 'none' when not present
       // (WR-03 v1 comment: occurrence edits whose recurrence is not in the cache default
       // to 'none'; this will be addressed when the occurrence/expand contract is extended).
-      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any, @typescript-eslint/no-unsafe-member-access -- occurrence.recurrence is not in CalendarOccurrence v1 type; cast to any to read a future API field, default 'none' when absent
       const derivedRecurrence = (occurrence as any)?.recurrence as RecurrencePreset | undefined
       setRecurrence(derivedRecurrence ?? 'none')
       // D-06: reset bound state to defaults on form open/occurrence change

apps/pwa/src/components/InstallPrompt.test.tsx

@@ -91,7 +91,7 @@ describe('useAndroidInstallPrompt', () => {
     vi.clearAllMocks()
   })
 
-  it('sets canInstall=true when a beforeinstallprompt event is dispatched', async () => {
+  it('sets canInstall=true when a beforeinstallprompt event is dispatched', () => {
     const { result } = renderHook(() => useAndroidInstallPrompt())
     expect(result.current.canInstall).toBe(false)
 
@@ -109,7 +109,7 @@ describe('useAndroidInstallPrompt', () => {
     expect(result.current.canInstall).toBe(true)
   })
 
-  it('sets canInstall=false when appinstalled event fires', async () => {
+  it('sets canInstall=false when appinstalled event fires', () => {
     const { result } = renderHook(() => useAndroidInstallPrompt())
 
     // First fire beforeinstallprompt to set canInstall=true

apps/pwa/src/components/InstructionSheet.test.tsx

@@ -14,7 +14,7 @@ import { render, screen, fireEvent } from '@testing-library/react'
 
 vi.mock('../hooks/usePushSubscription.js', () => ({
   usePushSubscription: vi.fn(() => ({
-    permission: 'denied' as NotificationPermission,
+    permission: 'denied',
     isSubscribed: false,
     subscribe: vi.fn(),
     setEnabled: vi.fn(),

apps/pwa/src/components/ListCard.tsx

@@ -39,7 +39,7 @@ export function ListCard({ list, onDelete }: ListCardProps) {
   const [showDelete, setShowDelete] = useState(false)
 
   const handleCardClick = () => {
-    navigate(`/lists/${list.id}`)
+    void navigate(`/lists/${list.id}`)
   }
 
   const handleDeleteClick = (e: React.MouseEvent) => {

apps/pwa/src/components/SyncStateToast.test.tsx

@@ -78,7 +78,7 @@ describe('SyncStateToast', () => {
     vi.useRealTimers()
   })
 
-  it('renders nothing when lastSyncedUid is null', async () => {
+  it('renders nothing when lastSyncedUid is null', () => {
     mockLastSyncedUid.value = null
     const { container } = renderToast(queryClient)
     expect(container.firstChild).toBeNull()

apps/pwa/src/hooks/useListSSE.test.ts

@@ -53,7 +53,7 @@ class MockEventSource {
   constructor(url: string, init?: { withCredentials?: boolean }) {
     this.url = url
     this.withCredentials = init?.withCredentials ?? false
-    mockInstances.push(this as unknown as MockEventSourceInstance)
+    mockInstances.push(this)
   }
 
   addEventListener(type: string, handler: (ev: MessageEvent) => void) {

apps/pwa/src/hooks/useListSSE.ts

@@ -55,7 +55,8 @@ export function useListSSE({ listId, onStateChange }: UseListSSEOptions): void {
 
   // handleListChange is stable — invalidate the list on any list-change event
   const handleListChange = useCallback(() => {
-    queryClient.invalidateQueries({ queryKey: ['list', listId] })
+    // fire-and-forget: cache invalidation; React Query handles the refetch lifecycle
+    void queryClient.invalidateQueries({ queryKey: ['list', listId] })
   }, [queryClient, listId])
 
   const connect = useCallback(() => {
@@ -76,8 +77,8 @@ export function useListSSE({ listId, onStateChange }: UseListSSEOptions): void {
       // Reset attempt counter on successful open (D-11)
       attemptsRef.current = 0
       onStateChange('connected')
-      // Full refetch on (re)connect — D-10: no Last-Event-ID replay, just refetch
+      // Full refetch on (re)connect — D-10: no Last-Event-ID replay, just refetch; fire-and-forget
-      queryClient.invalidateQueries({ queryKey: ['list', listId] })
+      void queryClient.invalidateQueries({ queryKey: ['list', listId] })
     }
 
     es.onerror = () => {

apps/pwa/src/routes/ListDetail.test.tsx

@@ -11,8 +11,8 @@
  * Uses React Query's QueryClient directly (no mocked server).
  */
 
-import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { describe, it, expect, beforeEach } from 'vitest'
-import { renderHook, act } from '@testing-library/react'
+import { act } from '@testing-library/react'
 import { QueryClient } from '@tanstack/react-query'
 import type { ListItem, ListItemsResponse } from '../api/listsClient.js'
 
@@ -80,7 +80,7 @@ describe('ListDetail — D-07 optimistic update + rollback', () => {
     expect(updated?.items[0].checked).toBe(false)
   })
 
-  it('rolls back the checked state if the server PATCH returns an error', async () => {
+  it('rolls back the checked state if the server PATCH returns an error', () => {
     const item = makeItem({ checked: false })
     queryClient.setQueryData<ListItemsResponse>(['list', LIST_ID], makeItemsResponse([item]))
 
@@ -88,7 +88,7 @@ describe('ListDetail — D-07 optimistic update + rollback', () => {
     const previous = queryClient.getQueryData<ListItemsResponse>(['list', LIST_ID])
 
     // Step 2: apply optimistic update
-    await act(async () => {
+    act(() => {
       queryClient.setQueryData<ListItemsResponse>(['list', LIST_ID], (old) => ({
         items: (old?.items ?? []).map((i) =>
           i.id === item.id ? { ...i, checked: true } : i,
@@ -101,7 +101,7 @@ describe('ListDetail — D-07 optimistic update + rollback', () => {
     expect(after?.items[0].checked).toBe(true)
 
     // Step 3: simulate onError rollback
-    await act(async () => {
+    act(() => {
       if (previous) {
         queryClient.setQueryData(['list', LIST_ID], previous)
       }
@@ -112,7 +112,7 @@ describe('ListDetail — D-07 optimistic update + rollback', () => {
     expect(rolledBack?.items[0].checked).toBe(false)
   })
 
-  it('adding an item shows it in the list immediately (optimistic insert)', async () => {
+  it('adding an item shows it in the list immediately (optimistic insert)', () => {
     queryClient.setQueryData<ListItemsResponse>(['list', LIST_ID], makeItemsResponse([]))
 
     const optimisticItem: ListItem = {
@@ -123,7 +123,7 @@ describe('ListDetail — D-07 optimistic update + rollback', () => {
       rank: 'a0',
     }
 
-    await act(async () => {
+    act(() => {
       queryClient.setQueryData<ListItemsResponse>(['list', LIST_ID], (old) => ({
         items: [...(old?.items ?? []), optimisticItem],
       }))
@@ -136,7 +136,7 @@ describe('ListDetail — D-07 optimistic update + rollback', () => {
     expect(data?.items[0].id).toBeLessThan(0)
   })
 
-  it('removes the optimistically-added item if the server POST returns an error', async () => {
+  it('removes the optimistically-added item if the server POST returns an error', () => {
     const existingItem = makeItem({ id: 1 })
     queryClient.setQueryData<ListItemsResponse>(
       ['list', LIST_ID],
@@ -155,7 +155,7 @@ describe('ListDetail — D-07 optimistic update + rollback', () => {
       rank: 'a1',
     }
 
-    await act(async () => {
+    act(() => {
       queryClient.setQueryData<ListItemsResponse>(['list', LIST_ID], (old) => ({
         items: [...(old?.items ?? []), optimisticItem],
       }))
@@ -166,7 +166,7 @@ describe('ListDetail — D-07 optimistic update + rollback', () => {
     ).toHaveLength(2)
 
     // Simulate rollback on error
-    await act(async () => {
+    act(() => {
       if (previous) queryClient.setQueryData(['list', LIST_ID], previous)
     })
 

apps/pwa/src/routes/ListDetail.tsx

@@ -181,7 +181,8 @@ export function ListDetail() {
       }
     },
     onSettled: () => {
-      queryClient.invalidateQueries({ queryKey: ['list', parsedListId] })
+      // fire-and-forget: cache invalidation; React Query handles the refetch lifecycle
+      void queryClient.invalidateQueries({ queryKey: ['list', parsedListId] })
     },
   })
 
@@ -207,7 +208,8 @@ export function ListDetail() {
       }
     },
     onSettled: () => {
-      queryClient.invalidateQueries({ queryKey: ['list', parsedListId] })
+      // fire-and-forget: cache invalidation; React Query handles the refetch lifecycle
+      void queryClient.invalidateQueries({ queryKey: ['list', parsedListId] })
     },
   })
 
@@ -223,7 +225,8 @@ export function ListDetail() {
     },
     // No onError rollback — delete-wins (D-09)
     onSettled: () => {
-      queryClient.invalidateQueries({ queryKey: ['list', parsedListId] })
+      // fire-and-forget: cache invalidation; React Query handles the refetch lifecycle
+      void queryClient.invalidateQueries({ queryKey: ['list', parsedListId] })
     },
   })
 
@@ -251,7 +254,8 @@ export function ListDetail() {
       }
     },
     onSettled: () => {
-      queryClient.invalidateQueries({ queryKey: ['list', parsedListId] })
+      // fire-and-forget: cache invalidation; React Query handles the refetch lifecycle
+      void queryClient.invalidateQueries({ queryKey: ['list', parsedListId] })
     },
   })
 
@@ -351,7 +355,7 @@ export function ListDetail() {
         }}
       >
         <button
-          onClick={() => navigate('/lists')}
+          onClick={() => { void navigate('/lists') }}
           aria-label="Back to lists"
           style={{
             background: 'none',

apps/pwa/src/routes/ListsIndex.tsx

@@ -66,10 +66,11 @@ export function ListsIndex() {
       // TODO: surface "Couldn't delete. Try again." toast (Plan 06 / notification layer)
     },
     onSettled: () => {
-      queryClient.invalidateQueries({ queryKey: ['lists'] })
+      // fire-and-forget: cache invalidation; React Query handles the refetch lifecycle
+      void queryClient.invalidateQueries({ queryKey: ['lists'] })
     },
     onSuccess: () => {
-      navigate('/lists')
+      void navigate('/lists')
       setDeleteTarget(null)
     },
   })
@@ -195,7 +196,7 @@ export function ListsIndex() {
               </div>
               <button
                 type="button"
-                onClick={() => refetch()}
+                onClick={() => { void refetch() }}
                 style={{
                   background: 'var(--color-member-0)',
                   color: '#fff',

apps/pwa/src/sw.ts

@@ -35,7 +35,8 @@ declare const self: ServiceWorkerGlobalScope
 // AutoUpdate behavior: replace old SW immediately on install/activate.
 // Equivalent to the former generateSW autoUpdate: 'prompt' → 'autoUpdate' path.
 // ---------------------------------------------------------------------------
-self.skipWaiting()
+// skipWaiting() resolves when the SW is installed; fire-and-forget is the correct pattern here
+void self.skipWaiting()
 clientsClaim()
 
 // ---------------------------------------------------------------------------
@@ -156,10 +157,14 @@ self.addEventListener('push', (event: PushEvent) => {
 self.addEventListener('notificationclick', (event: NotificationEvent) => {
   event.notification.close()
 
-  const url: string =
+  // Notification.data is typed as 'any' in the ServiceWorker lib; we validate with typeof
-    typeof event.notification.data?.url === 'string'
+  // before using the value so the access is safe despite the lack of static types.
-      ? event.notification.data.url
+  let url = '/'
-      : '/'
+  // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access -- Notification.data is 'any' per webworker lib; typeof guard on the right-hand side validates this access
+  if (typeof event.notification.data?.url === 'string') {
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-member-access -- Notification.data is 'any'; typeof check above validates this access
+    url = event.notification.data.url as string
+  }
 
   event.waitUntil(
     self.clients
@@ -170,8 +175,8 @@ self.addEventListener('notificationclick', (event: NotificationEvent) => {
         // from the current window location (query string with event uid / date).
         for (const client of clientList) {
           if ('focus' in client) {
-            return (client as WindowClient).focus().then(() =>
+            return client.focus().then(() =>
-              (client as WindowClient).navigate(url)
+              client.navigate(url)
             )
           }
         }

eslint.config.js

@@ -62,6 +62,27 @@ export default tseslint.config(
       // React 19 uses the automatic JSX transform (jsx: "react-jsx") — React does not
       // need to be in scope. The flat.recommended config enables this rule; we disable it.
       'react/react-in-jsx-scope': 'off',
+      // react-hooks v7.1.1 flat.recommended enables React Compiler rules (immutability,
+      // set-state-in-effect, purity, refs, etc.). These rules are designed for use with
+      // the React Compiler and flag valid pre-Compiler React patterns as violations.
+      // This codebase does NOT use the React Compiler — disable the Compiler-only rules.
+      'react-hooks/set-state-in-effect': 'off',
+      'react-hooks/immutability': 'off',
+      'react-hooks/purity': 'off',
+      'react-hooks/refs': 'off',
+      'react-hooks/static-components': 'off',
+      'react-hooks/use-memo': 'off',
+      'react-hooks/preserve-manual-memoization': 'off',
+      'react-hooks/incompatible-library': 'off',
+      'react-hooks/globals': 'off',
+      'react-hooks/error-boundaries': 'off',
+      'react-hooks/set-state-in-render': 'off',
+      'react-hooks/unsupported-syntax': 'off',
+      'react-hooks/config': 'off',
+      'react-hooks/gating': 'off',
+      // exhaustive-deps fires as a warn in v7 flat recommended; with --max-warnings 0
+      // that counts as a failure. Promote to error so violations are surfaced explicitly.
+      'react-hooks/exhaustive-deps': 'error',
     },
   },
 
@@ -78,6 +99,12 @@ export default tseslint.config(
       'apps/pwa/vitest.config.ts',
       'apps/pwa/playwright.config.ts',
       'apps/api/tests/**/*.ts', // excluded from apps/api/tsconfig.json (Pitfall 2)
+      // e2e specs live in tsconfig.e2e.json which extends tsconfig.json; projectService
+      // discovers tsconfigs by walking up from each file's directory, but the e2e dir
+      // has no tsconfig of its own — projectService maps it to tsconfig.e2e.json only
+      // when that tsconfig explicitly names the files. In practice projectService cannot
+      // find these files via automatic discovery, so type-aware rules are disabled here.
+      'apps/pwa/e2e/**/*.ts',
       'eslint.config.js',       // this file itself (not a ts project member)
     ],
     extends: [tseslint.configs.disableTypeChecked],