feat(04-01): wire BrowserRouter + BottomTabBar + empty Lists surface

- App.tsx: BrowserRouter with /calendar, /lists, /lists/:listId routes; / redirects to /calendar
- BottomTabBar.tsx: fixed-bottom 56px tab bar with Calendar + Lists NavLinks, active accent
- AppNav.tsx: add Calendar/Lists NavLinks to desktop sidebar (≥768px)
- ListsIndex.tsx: full-height surface with isLoading/isError/empty state branches; "+ New List" FAB placeholder
- ListDetail.tsx: placeholder stub for /lists/:listId (Plan 04-04 fills in)
- listsStore.ts: Zustand UI-only store (activeTab, createListSheetOpen)
- listsClient.ts: fetchLists + List/ListItem types (initial; Plans 04-02/03 expand)
- Fix Wave-0 RED stubs: add vitest imports so stubs execute (todo) not error on import
- Fix CalendarShell.test.tsx: wrap renderWithClient in MemoryRouter (AppNav uses NavLink)

apps/pwa/src/App.tsx

@@ -1,5 +1,38 @@
+/**
+ * App — BrowserRouter shell with react-router declarative routing.
+ *
+ * Routes:
+ *   /             → redirect to /calendar
+ *   /calendar     → CalendarShell
+ *   /lists        → ListsIndex
+ *   /lists/:listId → ListDetail (placeholder for Plan 04-04)
+ *
+ * BottomTabBar is rendered as a sibling of <Routes> so it persists across route
+ * changes. On desktop (≥768px) AppNav sidebar handles navigation — BottomTabBar
+ * is only visible on phone via CSS, but we render it in the tree at all sizes so
+ * the tab state remains consistent.
+ *
+ * navigateFallback ('/index.html') in vite.config.ts covers SPA deep-links to
+ * /lists/* — the SW denylist only excludes /callback, /api/, and /health, so
+ * /lists/* is served from cache correctly.
+ */
+
+import { BrowserRouter, Routes, Route, Navigate } from 'react-router'
 import { CalendarShell } from './components/CalendarShell.js'
+import { ListsIndex } from './routes/ListsIndex.js'
+import { ListDetail } from './routes/ListDetail.js'
+import { BottomTabBar } from './components/BottomTabBar.js'
 
 export default function App() {
-  return <CalendarShell />
+  return (
+    <BrowserRouter>
+      <Routes>
+        <Route path="/" element={<Navigate to="/calendar" replace />} />
+        <Route path="/calendar" element={<CalendarShell />} />
+        <Route path="/lists" element={<ListsIndex />} />
+        <Route path="/lists/:listId" element={<ListDetail />} />
+      </Routes>
+      <BottomTabBar />
+    </BrowserRouter>
+  )
 }

apps/pwa/src/api/listsClient.ts

@@ -0,0 +1,47 @@
+/**
+ * Typed API client for the FamilySync lists API.
+ *
+ * credentials: 'include' is required so the OIDC session cookie is sent with
+ * every request (same pattern as client.ts).
+ *
+ * This file provides only the functions needed in Plan 04-01 (ListsIndex empty
+ * state). Plans 04-02 and 04-03 expand it with createList, deleteList, item CRUD.
+ */
+
+const BASE = '/api'
+
+async function apiFetch(path: string, init?: RequestInit): Promise<Response> {
+  const res = await fetch(`${BASE}${path}`, {
+    credentials: 'include',
+    ...init,
+  })
+  if (!res.ok) throw new Error(`${init?.method ?? 'GET'} ${path} failed: ${res.status}`)
+  return res
+}
+
+// ── Types ──────────────────────────────────────────────────────────────────
+
+export interface List {
+  id: number
+  name: string
+  isShared: boolean
+  ownerId: number
+}
+
+export interface ListItem {
+  id: number
+  listId: number
+  text: string
+  checked: boolean
+  rank: string
+}
+
+export interface ListsResponse {
+  lists: List[]
+}
+
+// ── Functions ──────────────────────────────────────────────────────────────
+
+export async function fetchLists(): Promise<ListsResponse> {
+  return apiFetch('/lists').then((r) => r.json() as Promise<ListsResponse>)
+}

apps/pwa/src/components/AppNav.tsx

@@ -11,6 +11,8 @@
  *   - Grid is primary focal point; AppNav is secondary chrome
  */
 
+import { NavLink } from 'react-router'
+import { CalendarDays, List } from 'lucide-react'
 import { ColorLegend, type LegendMember } from './ColorLegend.js'
 
 interface AppNavProps {
@@ -102,8 +104,23 @@ function PhoneNav({
   )
 }
 
-/** Tablet/Desktop: 240px left sidebar — app name + color legend */
+/** Tablet/Desktop: 240px left sidebar — app name + nav links + color legend */
 function DesktopNav({ members }: { members: LegendMember[] }) {
+  const navLinkStyle = ({ isActive }: { isActive: boolean }): React.CSSProperties => ({
+    display: 'flex',
+    alignItems: 'center',
+    gap: '10px',
+    padding: 'var(--space-2) var(--space-3, 12px)',
+    borderRadius: 'var(--space-1, 4px)',
+    textDecoration: 'none',
+    fontSize: 'var(--text-body-size, 15px)',
+    fontWeight: isActive ? 600 : 400,
+    color: isActive ? 'var(--color-member-0)' : 'var(--color-text-primary)',
+    background: isActive ? 'color-mix(in srgb, var(--color-member-0) 10%, transparent)' : 'transparent',
+    minHeight: '44px',
+    transition: 'color 0.1s ease, background 0.1s ease',
+  })
+
   return (
     <nav
       style={{
@@ -133,6 +150,25 @@ function DesktopNav({ members }: { members: LegendMember[] }) {
         FamilySync
       </div>
 
+      {/* Section nav links */}
+      <div
+        style={{
+          display: 'flex',
+          flexDirection: 'column',
+          gap: 'var(--space-1, 4px)',
+          marginBottom: 'var(--space-6)',
+        }}
+      >
+        <NavLink to="/calendar" style={navLinkStyle} aria-label="Calendar">
+          <CalendarDays size={18} aria-hidden="true" />
+          Calendar
+        </NavLink>
+        <NavLink to="/lists" style={navLinkStyle} aria-label="Lists">
+          <List size={18} aria-hidden="true" />
+          Lists
+        </NavLink>
+      </div>
+
       {/* Color legend */}
       <div
         style={{

apps/pwa/src/components/BottomTabBar.tsx

@@ -0,0 +1,88 @@
+/**
+ * BottomTabBar — fixed-bottom navigation for phone (≤767px).
+ *
+ * UI-SPEC §BottomTabBar:
+ *   - Fixed bottom, full-width, 56px + env(safe-area-inset-bottom)
+ *   - Background: var(--color-surface-dim)
+ *   - Border-top: 1px solid var(--color-border)
+ *   - Two equal tabs: Calendar (CalendarDays icon) and Lists (List icon)
+ *   - Active tab: icon + label in var(--color-member-0), 2px border-bottom indicator
+ *   - Inactive tab: icon + label in var(--color-text-muted)
+ *   - Touch target: min 44px guaranteed by 56px bar height
+ *   - z-index: 200 (below dialogs at 300)
+ *
+ * Uses react-router NavLink for real-URL active detection (D-17).
+ * Only rendered on phone — DesktopNav handles desktop navigation.
+ */
+
+import { NavLink } from 'react-router'
+import { CalendarDays, List } from 'lucide-react'
+
+const tabBase: React.CSSProperties = {
+  flex: 1,
+  display: 'flex',
+  flexDirection: 'column',
+  alignItems: 'center',
+  justifyContent: 'center',
+  gap: '3px',
+  textDecoration: 'none',
+  fontSize: 'var(--text-label-size, 13px)',
+  fontWeight: 400,
+  lineHeight: 'var(--text-label-line-height, 1.4)',
+  fontFamily: 'var(--font-family-base)',
+  color: 'var(--color-text-muted)',
+  minHeight: '44px',
+  borderBottom: '2px solid transparent',
+  transition: 'color 0.1s ease, border-color 0.1s ease',
+  userSelect: 'none',
+  WebkitTapHighlightColor: 'transparent',
+}
+
+const tabActiveOverride: React.CSSProperties = {
+  color: 'var(--color-member-0)',
+  borderBottom: '2px solid var(--color-member-0)',
+}
+
+export function BottomTabBar() {
+  return (
+    <nav
+      aria-label="Main navigation"
+      style={{
+        position: 'fixed',
+        bottom: 0,
+        left: 0,
+        right: 0,
+        height: 'calc(56px + env(safe-area-inset-bottom, 0px))',
+        paddingBottom: 'env(safe-area-inset-bottom, 0px)',
+        display: 'flex',
+        background: 'var(--color-surface-dim)',
+        borderTop: '1px solid var(--color-border)',
+        zIndex: 200,
+      }}
+    >
+      <NavLink
+        to="/calendar"
+        aria-label="Calendar"
+        style={({ isActive }) => ({
+          ...tabBase,
+          ...(isActive ? tabActiveOverride : {}),
+        })}
+      >
+        <CalendarDays size={22} aria-hidden="true" />
+        <span>Calendar</span>
+      </NavLink>
+
+      <NavLink
+        to="/lists"
+        aria-label="Lists"
+        style={({ isActive }) => ({
+          ...tabBase,
+          ...(isActive ? tabActiveOverride : {}),
+        })}
+      >
+        <List size={22} aria-hidden="true" />
+        <span>Lists</span>
+      </NavLink>
+    </nav>
+  )
+}

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

@@ -18,6 +18,7 @@ import React from 'react'
 import { describe, it, expect, vi, beforeEach, type Mock } from 'vitest'
 import { render, screen, waitFor } from '@testing-library/react'
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
+import { MemoryRouter } from 'react-router'
 
 // window.matchMedia is polyfilled in src/test-setup.ts (loaded via vitest.config setupFiles)
 
@@ -128,7 +129,9 @@ function makeQueryClient() {
 function renderWithClient(ui: React.ReactElement) {
   const client = makeQueryClient()
   return render(
-    <QueryClientProvider client={client}>{ui}</QueryClientProvider>,
+    <MemoryRouter initialEntries={['/calendar']}>
+      <QueryClientProvider client={client}>{ui}</QueryClientProvider>
+    </MemoryRouter>,
   )
 }
 

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

@@ -10,6 +10,8 @@
  * Run: pnpm --filter @familysync/pwa test
  */
 
+import { describe, it } from 'vitest'
+
 describe('useListSSE — D-11 bounded backoff', () => {
   it.todo('starts connected when EventSource fires the open event')
   it.todo('attempts to reconnect with exponential backoff on error')

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

@@ -9,6 +9,8 @@
  * Run: pnpm --filter @familysync/pwa test
  */
 
+import { describe, it } from 'vitest'
+
 describe('ListDetail — D-07 optimistic update + rollback', () => {
   it.todo('checking an item immediately updates the UI before server responds')
   it.todo('unchecking an item immediately updates the UI before server responds')

apps/pwa/src/routes/ListDetail.tsx

@@ -0,0 +1,46 @@
+/**
+ * ListDetail — Single list view (/lists/:listId).
+ *
+ * PLACEHOLDER: This is a stub route component for Plan 04-01.
+ * The full implementation (items, SSE, drag-to-reorder, etc.) is built in Plan 04-04.
+ *
+ * Purpose: allows react-router's /lists/:listId route to resolve without error
+ * so the BottomTabBar NavLink and any deep-link won't 404.
+ */
+
+export function ListDetail() {
+  return (
+    <div
+      style={{
+        display: 'flex',
+        flexDirection: 'column',
+        alignItems: 'center',
+        justifyContent: 'center',
+        height: '100%',
+        gap: '12px',
+        fontFamily: 'var(--font-family-base)',
+        padding: '0 var(--space-4, 16px)',
+        textAlign: 'center',
+        paddingBottom: 'calc(56px + env(safe-area-inset-bottom, 0px))',
+      }}
+    >
+      <div
+        style={{
+          fontSize: 'var(--text-heading-size, 18px)',
+          fontWeight: 600,
+          color: 'var(--color-text-primary)',
+        }}
+      >
+        List view coming soon
+      </div>
+      <div
+        style={{
+          fontSize: 'var(--text-body-size, 15px)',
+          color: 'var(--color-text-muted)',
+        }}
+      >
+        Full list detail with live sync is being built in Phase 4 Plan 4.
+      </div>
+    </div>
+  )
+}

apps/pwa/src/routes/ListsIndex.tsx

@@ -0,0 +1,267 @@
+/**
+ * ListsIndex — Lists overview route (/lists).
+ *
+ * UI-SPEC §ListsIndex:
+ *   - Full-height scrollable column with 16px horizontal padding
+ *   - "Lists" heading
+ *   - FAB ("+ New List") — fixed bottom-right on phone, top-right inline on desktop
+ *   - Empty state: ListsEmptyState when no lists
+ *   - State branches: isLoading → skeleton, isError → error+retry, data → list cards
+ *
+ * Data flow:
+ *   TanStack Query ['lists'] → fetchLists → render list or empty state
+ *
+ * Note: Create + delete logic landed in Plans 04-02/04-03.
+ *       The FAB is a non-functional placeholder here (Plan 04-03 wires CreateListSheet).
+ */
+
+import { useQuery } from '@tanstack/react-query'
+import { Plus } from 'lucide-react'
+import { fetchLists, type List } from '../api/listsClient.js'
+
+// ── Empty State ────────────────────────────────────────────────────────────
+
+function ListsEmptyState() {
+  return (
+    <div
+      style={{
+        display: 'flex',
+        flexDirection: 'column',
+        alignItems: 'center',
+        justifyContent: 'center',
+        flex: 1,
+        padding: '48px var(--space-4)',
+        gap: 'var(--space-4)',
+        textAlign: 'center',
+        fontFamily: 'var(--font-family-base)',
+      }}
+    >
+      <div
+        style={{
+          fontSize: 'var(--text-heading-size, 18px)',
+          fontWeight: 600,
+          color: 'var(--color-text-primary)',
+          lineHeight: 'var(--text-heading-line-height, 1.25)',
+        }}
+      >
+        No lists yet
+      </div>
+      <div
+        style={{
+          fontSize: 'var(--text-body-size, 15px)',
+          fontWeight: 400,
+          color: 'var(--color-text-muted)',
+          lineHeight: 'var(--text-body-line-height, 1.5)',
+          maxWidth: '280px',
+        }}
+      >
+        Tap + to create your first shared list&hellip;
+      </div>
+    </div>
+  )
+}
+
+// ── List Card (placeholder for Plan 04-03 full implementation) ─────────────
+
+function ListCard({ list }: { list: List }) {
+  return (
+    <div
+      style={{
+        background: 'var(--color-surface)',
+        border: '1px solid var(--color-border)',
+        borderRadius: '8px',
+        padding: 'var(--space-4) var(--space-6, 24px)',
+        boxShadow: '0 1px 3px rgba(0,0,0,0.06)',
+        minHeight: '56px',
+        display: 'flex',
+        alignItems: 'center',
+        justifyContent: 'space-between',
+        fontFamily: 'var(--font-family-base)',
+        cursor: 'pointer',
+      }}
+    >
+      <div>
+        <div
+          style={{
+            fontSize: 'var(--text-heading-size, 18px)',
+            fontWeight: 600,
+            color: 'var(--color-text-primary)',
+            lineHeight: 'var(--text-heading-line-height, 1.25)',
+          }}
+        >
+          {list.name}
+        </div>
+        {list.isShared && (
+          <div
+            style={{
+              marginTop: '4px',
+              display: 'inline-block',
+              background: 'var(--color-surface-dim)',
+              color: 'var(--color-text-muted)',
+              fontSize: 'var(--text-label-size, 13px)',
+              fontWeight: 400,
+              padding: '2px 8px',
+              borderRadius: '4px',
+            }}
+          >
+            Shared
+          </div>
+        )}
+      </div>
+    </div>
+  )
+}
+
+// ── Main Component ─────────────────────────────────────────────────────────
+
+export function ListsIndex() {
+  const { data, isLoading, isError, refetch } = useQuery({
+    queryKey: ['lists'],
+    queryFn: fetchLists,
+    retry: 2,
+    staleTime: 30 * 1000,
+  })
+
+  const lists = data?.lists ?? []
+
+  return (
+    <div
+      style={{
+        display: 'flex',
+        flexDirection: 'column',
+        height: '100%',
+        minHeight: 0,
+        fontFamily: 'var(--font-family-base)',
+        // Bottom padding to clear the 56px fixed tab bar on phone
+        paddingBottom: 'calc(56px + env(safe-area-inset-bottom, 0px))',
+      }}
+    >
+      {/* Header */}
+      <div
+        style={{
+          display: 'flex',
+          alignItems: 'center',
+          justifyContent: 'space-between',
+          padding: 'var(--space-6, 24px) var(--space-4, 16px) var(--space-4, 16px)',
+          flexShrink: 0,
+        }}
+      >
+        <h1
+          style={{
+            margin: 0,
+            fontSize: 'var(--text-display-size, 24px)',
+            fontWeight: 600,
+            color: 'var(--color-text-primary)',
+            lineHeight: 'var(--text-display-line-height, 1.2)',
+          }}
+        >
+          Lists
+        </h1>
+
+        {/* FAB / inline button — non-functional placeholder until Plan 04-03 */}
+        <button
+          type="button"
+          aria-label="New list"
+          style={{
+            width: '44px',
+            height: '44px',
+            borderRadius: '50%',
+            background: 'var(--color-member-0)',
+            color: '#fff',
+            border: 'none',
+            cursor: 'pointer',
+            display: 'flex',
+            alignItems: 'center',
+            justifyContent: 'center',
+            flexShrink: 0,
+          }}
+        >
+          <Plus size={22} aria-hidden="true" />
+        </button>
+      </div>
+
+      {/* Content area */}
+      <div
+        style={{
+          flex: 1,
+          overflowY: 'auto',
+          padding: '0 var(--space-4, 16px)',
+          display: 'flex',
+          flexDirection: 'column',
+        }}
+      >
+        {/* Loading state */}
+        {isLoading && (
+          <div
+            style={{
+              padding: 'var(--space-8, 32px) 0',
+              color: 'var(--color-text-muted)',
+              fontSize: 'var(--text-body-size, 15px)',
+              textAlign: 'center',
+            }}
+          >
+            Loading lists&hellip;
+          </div>
+        )}
+
+        {/* Error state */}
+        {isError && !isLoading && (
+          <div
+            style={{
+              padding: 'var(--space-8, 32px) 0',
+              display: 'flex',
+              flexDirection: 'column',
+              alignItems: 'center',
+              gap: 'var(--space-4)',
+            }}
+          >
+            <div
+              style={{
+                color: 'var(--color-destructive)',
+                fontSize: 'var(--text-body-size, 15px)',
+              }}
+            >
+              Could not load lists
+            </div>
+            <button
+              type="button"
+              onClick={() => refetch()}
+              style={{
+                background: 'var(--color-member-0)',
+                color: '#fff',
+                border: 'none',
+                borderRadius: 'var(--space-1, 4px)',
+                padding: 'var(--space-2, 8px) var(--space-4, 16px)',
+                fontSize: 'var(--text-label-size, 13px)',
+                fontWeight: 600,
+                cursor: 'pointer',
+                minHeight: '44px',
+              }}
+            >
+              Retry
+            </button>
+          </div>
+        )}
+
+        {/* Empty state */}
+        {!isLoading && !isError && lists.length === 0 && <ListsEmptyState />}
+
+        {/* List cards */}
+        {!isLoading && !isError && lists.length > 0 && (
+          <div
+            style={{
+              display: 'flex',
+              flexDirection: 'column',
+              gap: 'var(--space-4, 16px)',
+              paddingBottom: 'var(--space-4, 16px)',
+            }}
+          >
+            {lists.map((list) => (
+              <ListCard key={list.id} list={list} />
+            ))}
+          </div>
+        )}
+      </div>
+    </div>
+  )
+}

apps/pwa/src/store/listsStore.ts

@@ -0,0 +1,36 @@
+/**
+ * Zustand UI-state store for the lists surface.
+ *
+ * Owns ONLY UI-shape state — no server data ever enters this store.
+ * Server state (lists, items) lives in TanStack Query.
+ *
+ * Convention: follows calendarStore.ts pattern — no persist middleware,
+ * no immer. State is ephemeral; lists UI state does not need persistence.
+ *
+ * State contract:
+ *   activeTab              — which bottom-tab is selected (drives tab active-state)
+ *   createListSheetOpen    — whether the "New List" sheet/dialog is open
+ */
+
+import { create } from 'zustand'
+
+// ── Types ──────────────────────────────────────────────────────────────────
+
+export interface ListsStore {
+  // UI-only state — no server data
+  activeTab: 'calendar' | 'lists'
+  createListSheetOpen: boolean
+
+  setActiveTab: (tab: 'calendar' | 'lists') => void
+  setCreateListSheetOpen: (open: boolean) => void
+}
+
+// ── Store ──────────────────────────────────────────────────────────────────
+
+export const useListsStore = create<ListsStore>()((set) => ({
+  activeTab: 'calendar',
+  createListSheetOpen: false,
+
+  setActiveTab: (tab) => set({ activeTab: tab }),
+  setCreateListSheetOpen: (open) => set({ createListSheetOpen: open }),
+}))