Remove JS obfuscator that broke Mapbox GL map rendering

vite-plugin-obfuscator processes ALL output chunks including vendor
libraries, corrupting Mapbox GL's WebGL shader string literals via
base64 encoding and string splitting. This caused the map to render
as a blank screen in production.

Vite's built-in esbuild minification already mangles identifiers and
removes whitespace, providing sufficient code protection.

Adds regression tests to prevent re-introducing obfuscation plugins.

frontend/package.json

@@ -65,7 +65,6 @@
     "tw-animate-css": "^1.3.4",
     "typescript": "~5.8.3",
     "typescript-eslint": "^8.30.1",
-    "vite": "^6.3.5",
-    "vite-plugin-obfuscator": "^1.0.5"
+    "vite": "^6.3.5"
   }
 }