refactor: make frontend a pure presentation layer fetching from backend API

Server components now fetch composed data from the backend instead of
directly querying SQLite and external APIs. Removes better-sqlite3
dependency from the frontend entirely.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

next.config.ts

@@ -11,8 +11,6 @@ const CSP = [
 ].join("; ");
 
 const nextConfig: NextConfig = {
-  // better-sqlite3 is a native module — must not be bundled by webpack
-  serverExternalPackages: ["better-sqlite3"],
   output: "standalone",
 
   async headers() {