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/Dockerfile.api

@@ -0,0 +1,32 @@
+FROM node:22-alpine AS base
+RUN npm install -g pnpm
+
+FROM base AS deps
+WORKDIR /app
+COPY package.json pnpm-workspace.yaml pnpm-lock.yaml* ./
+COPY packages/shared-types/package.json ./packages/shared-types/
+COPY services/api/package.json ./services/api/
+RUN pnpm install --frozen-lockfile
+
+FROM base AS builder
+WORKDIR /app
+COPY --from=deps /app/node_modules ./node_modules
+COPY --from=deps /app/packages/shared-types/node_modules ./packages/shared-types/node_modules
+COPY --from=deps /app/services/api/node_modules ./services/api/node_modules
+COPY tsconfig.base.json ./
+COPY packages/shared-types ./packages/shared-types
+COPY services/api ./services/api
+RUN pnpm --filter @oo/shared-types build
+RUN pnpm --filter @oo/api build
+
+FROM node:22-alpine AS runner
+WORKDIR /app
+RUN npm install -g pnpm
+COPY package.json pnpm-workspace.yaml ./
+COPY packages/shared-types/package.json ./packages/shared-types/
+COPY services/api/package.json ./services/api/
+RUN pnpm install --prod --frozen-lockfile
+COPY --from=builder /app/packages/shared-types/dist ./packages/shared-types/dist
+COPY --from=builder /app/services/api/dist ./services/api/dist
+WORKDIR /app/services/api
+CMD ["node", "dist/index.js"]