db: drizzle schema matching spec 02, initial migrations, settings service

Migration 0000 enables citext; 0001 creates all 39 tables. DB tests use a
throwaway database per file (TEST_DATABASE_URL, derived from .env in dev,
a postgres service in CI). Decision 0002: pg driver and @fastify/cookie.

Task: M1-T1

.github/workflows/ci.yml

@@ -8,6 +8,17 @@ on:
 jobs:
   check:
     runs-on: ubuntu-latest
+    services:
+      postgres:
+        image: postgres:18-alpine
+        env:
+          POSTGRES_USER: selfphoneng
+          POSTGRES_PASSWORD: ci
+          POSTGRES_DB: selfphoneng
+        options: >-
+          --health-cmd "pg_isready -U selfphoneng" --health-interval 5s --health-retries 20
+    env:
+      TEST_DATABASE_URL: postgres://selfphoneng:ci@postgres:5432/selfphoneng
     steps:
       - uses: actions/checkout@v4
       - uses: pnpm/action-setup@v4 # version comes from package.json "packageManager"