chore: clean up frontend dev config

- Update vite.config.ts HMR host to 192.168.0.94 for container dev
- Remove obsolete .env.dev and .env.prod files
- These old env files contained outdated anon keys causing 401 errors
- .env.development is now the single source of truth for dev config

vite.config.ts

@@ -100,7 +100,7 @@ export default defineConfig(({ mode }) => {
       } : {
         // Direct HTTP development
         protocol: 'ws',
-        host: 'localhost',
+        host: '192.168.0.94',
         port: parseInt(env.VITE_PORT_FRONTEND_HMR || '5173'),
       },