chore(01-01): scaffold monorepo, Docker Compose stack, and Vitest harness

- pnpm workspace with apps/api (Hono/Drizzle) and apps/pwa (Vite/React 19)
- Pinned versions per RESEARCH: hono@4.12.23, drizzle-orm@0.45.2, mysql2@3.22.4, tsdav@2.2.2, ical.js@2.2.1, zod@^3.25.0, node-cron@^4.2.1
- docker-compose.yml with mariadb:11 healthcheck, api depends_on service_healthy, redis stub
- docker-compose.dev.yml overrides for local dev (bind mounts, exposed ports)
- .env.example lists all env vars (DB_*, OIDC_*, APP_PASSWORD_ENCRYPTION_KEY)
- .gitignore excludes .env (never commit secrets)
- apps/api/vitest.config.ts with environment: node
- Wave 0 test stubs: health, auth/user, broker/crypto, broker/sync, broker/poller

apps/api/tests/helpers/db.ts

@@ -0,0 +1,59 @@
+/**
+ * Test DB fixture helpers.
+ *
+ * For unit tests (Tasks 1-2 scope): provides mock/stub helpers so tests can run
+ * without a real MariaDB connection. Plan 02/03 will fill in integration-style
+ * fixtures that hit the Docker MariaDB (DB_HOST=127.0.0.1 from the dev compose override).
+ */
+
+// Re-export vi for convenience in test files
+export { vi } from 'vitest'
+
+/**
+ * Creates a minimal mock for the Drizzle `db` singleton.
+ * Replace individual methods per test as needed.
+ *
+ * Plan 02 (auth) will extend this with a real test-schema fixture.
+ * Plan 03 (broker) will extend with event-fixture helpers.
+ */
+export function createMockDb() {
+  return {
+    select: vi.fn().mockReturnThis(),
+    from: vi.fn().mockReturnThis(),
+    where: vi.fn().mockReturnThis(),
+    limit: vi.fn().mockResolvedValue([]),
+    insert: vi.fn().mockReturnThis(),
+    values: vi.fn().mockReturnThis(),
+    onDuplicateKeyUpdate: vi.fn().mockResolvedValue([{ id: 1 }]),
+    $returningId: vi.fn().mockResolvedValue([{ id: 1 }]),
+    execute: vi.fn().mockResolvedValue([]),
+  }
+}
+
+/**
+ * Sample VEVENT string for broker tests — a timed event (Plan 03).
+ */
+export const SAMPLE_VEVENT_TIMED = `BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//FamilySync//Test//EN
+BEGIN:VEVENT
+UID:test-timed-event-001@familysync
+DTSTART:20260615T100000Z
+DTEND:20260615T110000Z
+SUMMARY:Test Timed Event
+END:VEVENT
+END:VCALENDAR`
+
+/**
+ * Sample VEVENT string for broker tests — an all-day event (Plan 03).
+ */
+export const SAMPLE_VEVENT_ALLDAY = `BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//FamilySync//Test//EN
+BEGIN:VEVENT
+UID:test-allday-event-001@familysync
+DTSTART;VALUE=DATE:20260615
+DTEND;VALUE=DATE:20260616
+SUMMARY:Test All-Day Event
+END:VEVENT
+END:VCALENDAR`