fix: lazy DB initialization — useDb() called inside handlers, not at import

useRuntimeConfig() and better-sqlite3 were being called at module
top-level, which crashes during Nitro server startup. Now all DB
access is lazy via useDb(), and auth uses process.env directly.

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

server/api/ideas/index.get.ts

@@ -1,7 +1,8 @@
-import db from '../../utils/db'
+import { useDb } from '../../utils/db'
 import { isAdmin } from '../../utils/auth'
 
 export default defineEventHandler((event) => {
+  const db = useDb()
   const admin = isAdmin(event)
   const rows = admin
     ? db.prepare('SELECT * FROM ideas ORDER BY created_at DESC').all()