feat(m1): project foundation setup - Next.js 15, Tailwind, tooling, CI

- Configure Next.js 15 (App Router, Node.js runtime, serverExternalPackages for better-sqlite3/bcrypt)

- Add Tailwind CSS, PostCSS, tsconfig with @/* alias

- Create app structure (layout, page, globals.css)

- Create directory structure (lib, repositories, services, components, tests)

- Configure Vitest (alias, coverage), Playwright

- Add dependencies: next, react, better-sqlite3, bcrypt, react-markdown, etc.

- Add .env.example, CI workflow, next-env.d.ts

- Remove boilerplate src/example files

.github/workflows/ci.yml

@@ -0,0 +1,20 @@
+name: CI
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '24'
+      - run: npm ci
+      - run: npm run lint
+      - run: npm run typecheck
+      - run: npm test
+      - run: npm run build