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/health.test.ts

@@ -0,0 +1,16 @@
+/**
+ * Wave 0 stub — GET /health: 200 + real DB round-trip
+ *
+ * This test is a RED stub. Implementation lives in:
+ *   apps/api/src/routes/health.ts  (Task 2)
+ *
+ * The test will be filled GREEN in Task 2 when the health route is implemented.
+ */
+
+import { describe, it } from 'vitest'
+
+describe('GET /health', () => {
+  it.todo('returns 200 with { ok: true, db: "up" } after a real DB round-trip (Task 2)')
+
+  it.todo('returns 503 if the DB round-trip throws (Task 2)')
+})