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/utils/db.ts

@@ -0,0 +1,39 @@
+import Database from 'better-sqlite3'
+import { mkdirSync } from 'fs'
+import { dirname } from 'path'
+
+const config = useRuntimeConfig()
+const dbPath = config.dbPath as string
+
+mkdirSync(dirname(dbPath), { recursive: true })
+
+const db = new Database(dbPath)
+db.pragma('journal_mode = WAL')
+db.pragma('foreign_keys = ON')
+
+db.exec(`
+  CREATE TABLE IF NOT EXISTS ideas (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    text TEXT NOT NULL,
+    category TEXT NOT NULL DEFAULT 'General',
+    votes INTEGER NOT NULL DEFAULT 0,
+    hidden INTEGER NOT NULL DEFAULT 0,
+    created_at TEXT NOT NULL DEFAULT (datetime('now'))
+  );
+
+  CREATE TABLE IF NOT EXISTS vote_log (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    idea_id INTEGER NOT NULL REFERENCES ideas(id) ON DELETE CASCADE,
+    voter_hash TEXT NOT NULL,
+    created_at TEXT NOT NULL DEFAULT (datetime('now')),
+    UNIQUE(idea_id, voter_hash)
+  );
+
+  CREATE TABLE IF NOT EXISTS sessions (
+    token TEXT PRIMARY KEY,
+    created_at TEXT NOT NULL DEFAULT (datetime('now')),
+    expires_at TEXT NOT NULL
+  );
+`)
+
+export default db