Revert frontend/tsconfig.json changes

Restore original module and target configuration.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: KeHang-Zhu

frontend/tsconfig.json

@@ -9,7 +9,8 @@
     "target": "es2021",
     "outDir": "./dist/",
     "noImplicitAny": true,
-    "module": "es2020",
+    "module": "es6",
+    "target": "es6",
     "allowJs": true,
     "experimentalDecorators": true,
     "moduleResolution": "node",