refactor: replace TypeScript with ESM JavaScript

Remove index.ts and tsconfig.json, update package.json, and install dependencies.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

package.json

@@ -18,7 +18,6 @@
     "winston": "^3.11.0"
   },
   "devDependencies": {
-    "@types/bun": "latest",
     "drizzle-kit": "^0.31.10"
   }
 }