feat: Phase 0 walking skeleton — monorepo, API, web, ML stub

Sets up the full Phase 0 foundation:

- pnpm workspaces + turbo build graph; native module build approval
- packages/shared-types: HTTP contracts (Tip, Auth, Integrations, User)
- services/api: Express modular monolith with better-sqlite3/drizzle
  - auth: Google OAuth2 + PKCE via openid-client v6, cookie sessions
  - integrations: Todoist OAuth2 connect/disconnect, token vault
  - recommender: RandomPolicy over Todoist tasks, feedback sink
  - user: profile, consent capture, full account deletion (GDPR)
- apps/web: Next.js 15, three pages (sign-in → connect → tip)
  - tip page: black canvas, hold-to-act gesture, action sheet
  - PWA manifest + theme
- ml/serving: FastAPI stub implementing the POST /score contract
- infra: docker-compose (core/full profiles), Dockerfiles, CI skeleton
- .env.example with all required vars documented

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

infra/docker/docker-compose.yml

@@ -0,0 +1,56 @@
+name: oo
+
+services:
+  # ── core profile ──────────────────────────────────────────────────────────
+
+  api:
+    build:
+      context: ../..
+      dockerfile: infra/docker/Dockerfile.api
+    profiles: [core, full]
+    env_file: ../../.env.local
+    environment:
+      DATABASE_PATH: /data/oo.db
+      PORT: "3001"
+      NODE_ENV: production
+    volumes:
+      - api-data:/data
+    ports:
+      - "3001:3001"
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:3001/health"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
+  web:
+    build:
+      context: ../..
+      dockerfile: infra/docker/Dockerfile.web
+    profiles: [core, full]
+    env_file: ../../.env.local
+    environment:
+      NEXT_PUBLIC_API_URL: ""   # rewrites proxy to /api, no cross-origin needed in prod
+    ports:
+      - "3000:3000"
+    depends_on:
+      api:
+        condition: service_healthy
+
+  # ── full profile ──────────────────────────────────────────────────────────
+
+  ml-serving:
+    build:
+      context: ../..
+      dockerfile: infra/docker/Dockerfile.ml
+    profiles: [full]
+    ports:
+      - "8000:8000"
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:8000/health"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
+volumes:
+  api-data: