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>

package.json

@@ -0,0 +1,22 @@
+{
+  "name": "oo-monorepo",
+  "private": true,
+  "version": "0.0.0",
+  "packageManager": "pnpm@10.33.0",
+  "scripts": {
+    "build": "turbo build",
+    "dev": "turbo dev",
+    "lint": "turbo lint",
+    "type-check": "turbo type-check",
+    "test": "turbo test",
+    "clean": "turbo clean"
+  },
+  "pnpm": {
+    "onlyBuiltDependencies": ["better-sqlite3", "esbuild", "sharp"]
+  },
+  "devDependencies": {
+    "turbo": "^2.3.3",
+    "typescript": "^5.7.3",
+    "@types/node": "^22.10.5"
+  }
+}