chore: codebase audit — remove dead code, unused deps, clean configs

Phase 1: Delete 19 dead component/service/tool files (4,200+ lines)
Phase 2: Remove 13 unused npm packages (Radix UI, shadcn utilities, ytdl-core, etc.)
Phase 3: Database schema — drop agent_delegations, add performance indexes
Phase 4: Remove 12 dead types from database.ts/analytics.ts/helpers.ts
Phase 5: Strip shadcn/ui theme from tailwind config
Phase 6: Clean env vars, fix broken imports (LocalKeyGate, MapViewer)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/page.tsx

@@ -1,10 +1,5 @@
 import ThreePanelLayout from '@/components/layout/ThreePanelLayout';
-import { LocalKeyGate } from '@/components/auth/LocalKeyGate';
 
 export default function Home() {
-  return (
-    <LocalKeyGate>
-      <ThreePanelLayout />
-    </LocalKeyGate>
-  );
+  return <ThreePanelLayout />;
 }