feat(05-04): push subscription API + VAPID startup wiring

- Create apps/api/src/routes/push.ts: GET /vapid-public-key, POST /subscription (upsert), DELETE /subscription (user-scoped)
- Wire pushRouter at /api/push in index.ts
- Call webpush.setVapidDetails() in isMainModule() guard before serve()
- Fix broken vi.getMockImplementation scaffold bug in push.test.ts (Rule 1)
- push.test.ts: all 4 tests GREEN

apps/api/src/routes/push.ts

@@ -0,0 +1,139 @@
+/**
+ * Push router — VAPID public-key delivery + subscription lifecycle (NOTIF-01/02/03).
+ *
+ * Security (threat model T-05-09, T-05-10, T-05-13):
+ *   - GET /vapid-public-key: public key only; sits under /api OIDC guard (PWA fetches post-login).
+ *     The VAPID public key is non-secret — the private key is NEVER served.
+ *   - POST /subscription: zod-validated body; userId from OIDC session (T-05-09 spoofing
+ *     mitigation — client body never sets userId). Upsert on endpoint to handle re-subscribe.
+ *   - DELETE /subscription: scoped WHERE userId = caller — cannot delete another member's
+ *     subscription (T-05-13 access control).
+ *
+ * Mounted under /api/push in index.ts.
+ */
+
+import { Hono } from 'hono'
+import type { Context } from 'hono'
+import { zValidator } from '@hono/zod-validator'
+import { z } from 'zod'
+import { eq } from 'drizzle-orm'
+import { db } from '../db/client.js'
+import { pushSubscriptions } from '../db/schema.js'
+import { getAuth } from '../auth/middleware.js'
+import { upsertUser, deriveDisplayName } from '../auth/user.js'
+// Side-effect import: brings in the ContextVariableMap augmentation for c.get('user')
+import '../auth/devBypass.js'
+
+export const pushRouter = new Hono()
+
+// ---------------------------------------------------------------------------
+// Auth helper — Duplicated per router (not extracted to shared module).
+// Copied verbatim from lists.ts per project convention.
+//
+// Resolution order:
+//   1. Dev-bypass path: c.get('user') is set by devAuthBypass() when DEV_AUTH_BYPASS=true.
+//   2. OIDC path: call getAuth(c). If null → unauthenticated, return null.
+// ---------------------------------------------------------------------------
+async function resolveUserId(c: Context): Promise<number | null> {
+  const devUser = c.get('user') as { id: number } | undefined
+  if (devUser) return devUser.id
+
+  const auth = await getAuth(c)
+  if (!auth) return null
+
+  const iss = (auth.iss as string | undefined) ?? ''
+  const sub = auth.sub ?? ''
+  const displayName = deriveDisplayName(auth)
+  const user = await upsertUser(iss, sub, displayName)
+  return user?.id ?? null
+}
+
+// ---------------------------------------------------------------------------
+// Zod schemas
+// ---------------------------------------------------------------------------
+
+/**
+ * Subscribe body — validated per T-05-10 (input validation).
+ * Bounds: endpoint URL max 2048, p256dh max 512 (unpadded base64 of 65-byte P-256 key),
+ * auth max 256 (unpadded base64 of 16-byte auth secret).
+ */
+const subscribeSchema = z.object({
+  endpoint: z.string().url().max(2048),
+  keys: z.object({
+    p256dh: z.string().min(1).max(512),
+    auth: z.string().min(1).max(256),
+  }),
+})
+
+// ---------------------------------------------------------------------------
+// GET /api/push/vapid-public-key
+//
+// Serves the VAPID public key to the PWA. The public key is not a secret — it
+// is needed by the browser to compute the applicationServerKey for subscribe().
+// The PRIVATE key is NEVER returned.
+//
+// Sits under /api OIDC guard (acceptable for v1 — only authenticated members can
+// subscribe to push anyway).
+// ---------------------------------------------------------------------------
+pushRouter.get('/vapid-public-key', (c) => {
+  return c.json({ publicKey: process.env.VAPID_PUBLIC_KEY ?? '' })
+})
+
+// ---------------------------------------------------------------------------
+// POST /api/push/subscription
+//
+// Persists a push subscription row scoped to the authenticated user.
+// Upserts on endpoint (unique constraint) so re-subscribing from the same device
+// updates the ownership + keys without creating duplicate rows.
+//
+// Security: T-05-09 — userId derives from OIDC session, never from request body.
+//           T-05-10 — zod subscribeSchema validates all fields before DB write.
+// ---------------------------------------------------------------------------
+pushRouter.post('/subscription', zValidator('json', subscribeSchema), async (c) => {
+  const userId = await resolveUserId(c)
+  if (!userId) return c.json({ error: 'Unauthorized' }, 401)
+
+  const body = c.req.valid('json')
+
+  try {
+    await db
+      .insert(pushSubscriptions)
+      .values({
+        userId,
+        endpoint: body.endpoint,
+        p256dh: body.keys.p256dh,
+        auth: body.keys.auth,
+      })
+      .onDuplicateKeyUpdate({
+        set: {
+          userId,
+          p256dh: body.keys.p256dh,
+          auth: body.keys.auth,
+        },
+      })
+
+    return c.json({ ok: true }, 201)
+  } catch (err) {
+    console.error('[push/POST /subscription] DB operation failed:', err)
+    return c.json({ error: 'Service unavailable' }, 503)
+  }
+})
+
+// ---------------------------------------------------------------------------
+// DELETE /api/push/subscription
+//
+// Removes all push subscription rows for the authenticated user.
+// Scoped to caller only — cannot delete another member's subscriptions (T-05-13).
+// ---------------------------------------------------------------------------
+pushRouter.delete('/subscription', async (c) => {
+  const userId = await resolveUserId(c)
+  if (!userId) return c.json({ error: 'Unauthorized' }, 401)
+
+  try {
+    await db.delete(pushSubscriptions).where(eq(pushSubscriptions.userId, userId))
+    return c.json({ ok: true })
+  } catch (err) {
+    console.error('[push/DELETE /subscription] DB operation failed:', err)
+    return c.json({ error: 'Service unavailable' }, 503)
+  }
+})