Fix runtime errors: PerformanceObserver, localStorage, crypto.randomUUID, hydration issues, and linting errors

app/editor/page.tsx

@@ -59,7 +59,7 @@ function EditorPageContent() {
   const [isSaving, setIsSaving] = useState(false);
   const [isCreating, setIsCreating] = useState(!projectId);
   const [showPreview, setShowPreview] = useState(false);
-  const [isTyping, setIsTyping] = useState(false);
+  const [_isTyping, setIsTyping] = useState(false);
   const [history, setHistory] = useState<typeof formData[]>([]);
   const [historyIndex, setHistoryIndex] = useState(-1);
   const [originalFormData, setOriginalFormData] = useState<typeof formData | null>(null);