fix(hooks): resolve react-hooks/refs lint errors breaking CI

- useMarkCommentsRead: replace useRef().current with useCallback for
  stable ref callback (accessing ref during render is not allowed)
- useAttachments: add eslint-disable for intentional ref sync pattern

src/renderer/hooks/useAttachments.ts

@@ -61,6 +61,7 @@ export function useAttachments(options?: UseAttachmentsOptions): UseAttachmentsR
   // eslint-disable-next-line react-hooks/refs -- synchronous ref sync during render is intentional to avoid stale key in callbacks
   keyRef.current = persistenceKey;
   const onUnsupportedRef = useRef(options?.onUnsupportedFiles);
+  // eslint-disable-next-line react-hooks/refs -- synchronous ref sync during render is intentional to avoid stale callback in handlers
   onUnsupportedRef.current = options?.onUnsupportedFiles;
 
   // Sync ref with state

src/renderer/hooks/useMarkCommentsRead.ts

@@ -1,4 +1,4 @@
-import { useRef } from 'react';
+import { useCallback, useRef } from 'react';
 
 /**
  * Provides a stable ref callback for the comments container.
@@ -19,9 +19,9 @@ export function useMarkCommentsRead(
   const nodeRef = useRef<HTMLElement | null>(null);
 
   // Stable ref callback (no dependencies — just stores the node)
-  const refCallback = useRef((node: HTMLElement | null) => {
+  const refCallback = useCallback((node: HTMLElement | null) => {
     nodeRef.current = node;
-  }).current;
+  }, []);
 
   return refCallback;
 }