feat: initial brainstorming app — Nuxt 3 + SQLite + admin auth

Nuxt 3 app with:
- SQLite (better-sqlite3) for persistence
- Anonymous idea submission and voting
- Admin auth with session cookies
- AI analysis via Gemini API
- Nuxt UI components + Tailwind

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/api/ideas/index.get.ts

@@ -0,0 +1,10 @@
+import db from '../../utils/db'
+import { isAdmin } from '../../utils/auth'
+
+export default defineEventHandler((event) => {
+  const admin = isAdmin(event)
+  const rows = admin
+    ? db.prepare('SELECT * FROM ideas ORDER BY created_at DESC').all()
+    : db.prepare('SELECT * FROM ideas WHERE hidden = 0 ORDER BY created_at DESC').all()
+  return rows
+})