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

eslint.config.js

@@ -18,6 +18,16 @@ export default tseslint.config(
     },
   },
   {
-    ignores: ['node_modules/**', 'dist/**', '.steering/**'],
+    ignores: [
+      'node_modules/**',
+      'dist/**',
+      '.next/**',
+      '.steering/**',
+      'data/**',
+      'backups/**',
+      'playwright-report/**',
+      'test-results/**',
+      'next-env.d.ts',
+    ],
   }
 );