fix: infinite loop in useTaskDetail merge preview loading (#444)

* fix: infinite loop in useTaskDetail merge preview loading

The merge preview loading was caught in an infinite loop due to:
1. Effect clearing mergePreview state to null on task load
2. Auto-load effect seeing null and calling loadMergePreview()
3. React Strict Mode double-invoke causing cycle to repeat

Fixed by using a ref (hasLoadedPreviewRef) to track whether preview
has already been loaded for the current task, preventing unnecessary
reloads regardless of state changes.

Also removed excessive console.warn statements that were cluttering
the console output.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Signed-off-by: Abe Diaz (@abe238) <abe238@gmail.com>

* fix: address code review feedback for merge preview loading

- Move hasLoadedPreviewRef assignment to finally block to prevent
  infinite retry loop on API failures (Gemini/CodeRabbit feedback)
- Remove unused sessionStorage operations (dead code)
- Simplify comments

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Signed-off-by: Abe Diaz (@abe238) <abe238@gmail.com>

---------

Signed-off-by: Abe Diaz (@abe238) <abe238@gmail.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

apps/frontend/src/renderer/components/task-detail/hooks/useTaskDetail.ts

@@ -195,44 +195,29 @@ export function useTaskDetail({ task }: UseTaskDetailOptions) {
     });
   }, []);
 
-  // Clear merge preview cache when task changes to ensure fresh data is fetched
-  // This invalidates any stale cached data (e.g., old uncommitted changes status)
+  // Track if we've already loaded preview for this task to prevent infinite loops
+  const hasLoadedPreviewRef = useRef<string | null>(null);
+
+  // Clear merge preview state when switching to a different task
   useEffect(() => {
-    const storageKey = `mergePreview-${task.id}`;
-    // Clear any existing cached preview - we want fresh data when opening a task
-    sessionStorage.removeItem(storageKey);
-    setMergePreview(null);
-    console.warn('[useTaskDetail] Cleared merge preview cache for task:', task.id);
+    if (hasLoadedPreviewRef.current !== task.id) {
+      setMergePreview(null);
+      hasLoadedPreviewRef.current = null;
+    }
   }, [task.id]);
 
   // Load merge preview (conflict detection)
   const loadMergePreview = useCallback(async () => {
-    console.warn('%c[useTaskDetail] loadMergePreview called for task:', 'color: cyan; font-weight: bold;', task.id);
     setIsLoadingPreview(true);
     try {
-      console.warn('[useTaskDetail] Calling mergeWorktreePreview...');
       const result = await window.electronAPI.mergeWorktreePreview(task.id);
-      console.warn('%c[useTaskDetail] mergeWorktreePreview result:', 'color: lime; font-weight: bold;', JSON.stringify(result, null, 2));
       if (result.success && result.data?.preview) {
-        const previewData = result.data.preview;
-        console.warn('%c[useTaskDetail] Setting merge preview:', 'color: lime; font-weight: bold;', previewData);
-        console.warn('  - files:', previewData.files);
-        console.warn('  - conflicts:', previewData.conflicts);
-        console.warn('  - summary:', previewData.summary);
-        setMergePreview(previewData);
-        // Persist to sessionStorage to survive HMR reloads
-        sessionStorage.setItem(`mergePreview-${task.id}`, JSON.stringify(previewData));
-        // Don't auto-popup conflict dialog - let user click to see details if curious
-      } else {
-        console.warn('%c[useTaskDetail] Preview not successful or no preview data:', 'color: orange;', result);
-        console.warn('  - success:', result.success);
-        console.warn('  - data:', result.data);
-        console.warn('  - error:', result.error);
+        setMergePreview(result.data.preview);
       }
     } catch (err) {
-      console.error('%c[useTaskDetail] Failed to load merge preview:', 'color: red; font-weight: bold;', err);
+      console.error('[useTaskDetail] Failed to load merge preview:', err);
     } finally {
-      console.warn('[useTaskDetail] Setting isLoadingPreview to false');
+      hasLoadedPreviewRef.current = task.id;
       setIsLoadingPreview(false);
     }
   }, [task.id]);
@@ -243,13 +228,13 @@ export function useTaskDetail({ task }: UseTaskDetailOptions) {
     // Only auto-load if:
     // 1. Task needs review
     // 2. Worktree exists
-    // 3. We haven't already loaded the preview
+    // 3. We haven't already loaded the preview for this task
     // 4. We're not currently loading
-    if (needsReview && worktreeStatus?.exists && !mergePreview && !isLoadingPreview) {
-      console.warn('[useTaskDetail] Auto-loading merge preview for task:', task.id);
+    const alreadyLoaded = hasLoadedPreviewRef.current === task.id;
+    if (needsReview && worktreeStatus?.exists && !alreadyLoaded && !isLoadingPreview) {
       loadMergePreview();
     }
-  }, [needsReview, worktreeStatus?.exists, mergePreview, isLoadingPreview, task.id, loadMergePreview]);
+  }, [needsReview, worktreeStatus?.exists, isLoadingPreview, task.id, loadMergePreview]);
 
   return {
     // State