feat: Next.js + Tailwind + shadcn/ui project skeleton

- create-next-app with TypeScript, App Router, Tailwind CSS
- shadcn/ui initialized with defaults (button component + utils)
- .env.example with DATABASE_URL and SESSION_SECRET placeholders
- README.md with docs/runbooks/ reference

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

components.json

@@ -0,0 +1,25 @@
+{
+  "$schema": "https://ui.shadcn.com/schema.json",
+  "style": "base-nova",
+  "rsc": true,
+  "tsx": true,
+  "tailwind": {
+    "config": "",
+    "css": "app/globals.css",
+    "baseColor": "neutral",
+    "cssVariables": true,
+    "prefix": ""
+  },
+  "iconLibrary": "lucide",
+  "rtl": false,
+  "aliases": {
+    "components": "@/components",
+    "utils": "@/lib/utils",
+    "ui": "@/components/ui",
+    "lib": "@/lib",
+    "hooks": "@/hooks"
+  },
+  "menuColor": "default",
+  "menuAccent": "subtle",
+  "registries": {}
+}