fix: restrict PostHog debug logging to development only

frontend/src/main.tsx

@@ -17,11 +17,13 @@ const posthogOptions = {
   defaults: '2026-01-30',
 } as const
 
-// Debug PostHog configuration
+// Debug PostHog configuration (dev only)
+if (import.meta.env.DEV) {
   console.log('PostHog Config:', {
     apiKey: import.meta.env.VITE_PUBLIC_POSTHOG_KEY ? '✓ Set' : '✗ Missing',
     apiHost: import.meta.env.VITE_PUBLIC_POSTHOG_HOST,
   })
+}
 
 ReactDOM.createRoot(document.getElementById('root')!).render(
   <StrictMode>