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

vitest.config.ts

@@ -1,12 +1,15 @@
 import { defineConfig } from 'vitest/config';
+import path from 'node:path';
 
 export default defineConfig({
   test: {
     globals: true,
     environment: 'node',
     include: [
-      'src/**/*.{test,spec}.{ts,tsx}',
       'tests/**/*.{test,spec}.{ts,tsx}',
+      'lib/**/*.{test,spec}.{ts,tsx}',
+      'repositories/**/*.{test,spec}.{ts,tsx}',
+      'services/**/*.{test,spec}.{ts,tsx}',
     ],
     coverage: {
       provider: 'v8',
@@ -14,9 +17,11 @@ export default defineConfig({
       exclude: [
         'node_modules/**',
         'dist/**',
+        '.next/**',
         '.steering/**',
-        '**/*.config.{ts,js}',
+        '**/*.config.{ts,js,mjs}',
         '**/types/**',
+        'tests/**',
       ],
       thresholds: {
         branches: 80,
@@ -26,4 +31,9 @@ export default defineConfig({
       },
     },
   },
+  resolve: {
+    alias: {
+      '@': path.resolve(__dirname, '.'),
+    },
+  },
 });