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>

tsconfig.json

@@ -23,5 +23,5 @@
     }
   },
   "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx", ".next/types/**/*.ts"],
-  "exclude": ["node_modules"]
+  "exclude": ["node_modules", "backend"]
 }