chore(01-01): bootstrap Next.js 16 with TypeScript, App Router, Tailwind CSS v4

- Created Next.js 16.2.6 project with App Router, src/ directory, TypeScript strict mode
- Configured Tailwind CSS v4 with postcss.config.mjs
- Simplified src/app/page.tsx to Welcome to ClientHub placeholder
- Updated layout.tsx with ClientHub metadata, Italian lang, viewport export (Next.js 16 API)
- Added .gitignore covering node_modules, .env*, .next/, build artifacts

Note: create-next-app installed Next.js 16.2.6 (latest stable) instead of 15.x — fully compatible upgrade

tsconfig.json

@@ -0,0 +1,34 @@
+{
+  "compilerOptions": {
+    "target": "ES2017",
+    "lib": ["dom", "dom.iterable", "esnext"],
+    "allowJs": true,
+    "skipLibCheck": true,
+    "strict": true,
+    "noEmit": true,
+    "esModuleInterop": true,
+    "module": "esnext",
+    "moduleResolution": "bundler",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "jsx": "react-jsx",
+    "incremental": true,
+    "plugins": [
+      {
+        "name": "next"
+      }
+    ],
+    "paths": {
+      "@/*": ["./src/*"]
+    }
+  },
+  "include": [
+    "next-env.d.ts",
+    "**/*.ts",
+    "**/*.tsx",
+    ".next/types/**/*.ts",
+    ".next/dev/types/**/*.ts",
+    "**/*.mts"
+  ],
+  "exclude": ["node_modules"]
+}