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.post.ts

@@ -0,0 +1,11 @@
+import db from '../../utils/db'
+
+export default defineEventHandler(async (event) => {
+  const { text, category } = await readBody(event)
+  if (!text?.trim()) {
+    throw createError({ statusCode: 400, statusMessage: 'Text is required' })
+  }
+  const cat = category || 'General'
+  const result = db.prepare('INSERT INTO ideas (text, category) VALUES (?, ?)').run(text.trim(), cat)
+  return { id: result.lastInsertRowid }
+})