🤖 feat: add Shift+M shortcut to mark entire file as read in code review (#560)

When reviewing code with many hunks per file, marking each hunk
individually is tedious. **Shift+M** now marks all hunks in the current
file as read at once.

**Implementation:**
- New `MARK_FILE_READ` keybind triggers `handleMarkFileAsRead` 
- Finds all hunks with matching `filePath` and calls existing
`markAsRead(array)`
- Smart navigation: when hiding read hunks, jumps to next unread file
automatically
- Tooltip updated to show both shortcuts: **M** (single hunk) and
**Shift+M** (whole file)

**Verify:** Open review tab, select a hunk, press Shift+M. All hunks in
that file should be marked read.

_Generated with `cmux`_

Author: ammar-agent

src/components/RightSidebar/CodeReview/HunkViewer.tsx

@@ -230,7 +230,8 @@ export const HunkViewer = React.memo<HunkViewerProps>(
                   {isRead ? "○" : "◉"}
                 </button>
                 <Tooltip align="right" position="top">
-                  Mark as read ({formatKeybind(KEYBINDS.TOGGLE_HUNK_READ)})
+                  Mark as read ({formatKeybind(KEYBINDS.TOGGLE_HUNK_READ)}) · Mark file (
+                  {formatKeybind(KEYBINDS.MARK_FILE_READ)})
                 </Tooltip>
               </TooltipWrapper>
             )}

src/components/RightSidebar/CodeReview/ReviewPanel.tsx

@@ -467,6 +467,33 @@ export const ReviewPanel: React.FC<ReviewPanelProps> = ({
     toggleExpandFnsRef.current.set(hunkId, toggleFn);
   }, []);
 
+  // Handle marking all hunks in a file as read
+  const handleMarkFileAsRead = useCallback(
+    (hunkId: string) => {
+      // Find the hunk to determine its file path
+      const hunk = hunks.find((h) => h.id === hunkId);
+      if (!hunk) return;
+
+      // Find all hunks in the same file
+      const fileHunkIds = hunks.filter((h) => h.filePath === hunk.filePath).map((h) => h.id);
+
+      // Mark all hunks in the file as read
+      markAsRead(fileHunkIds);
+
+      // If marking the selected hunk's file as read and hunks will be filtered out, navigate
+      if (hunkId === selectedHunkId && !filters.showReadHunks) {
+        // Find the next visible hunk that's not in the same file
+        const currentFiltered = hunks.filter((h) => !isRead(h.id) && h.filePath !== hunk.filePath);
+        if (currentFiltered.length > 0) {
+          setSelectedHunkId(currentFiltered[0].id);
+        } else {
+          setSelectedHunkId(null);
+        }
+      }
+    },
+    [hunks, markAsRead, isRead, filters.showReadHunks, selectedHunkId]
+  );
+
   // Calculate stats
   const stats = useMemo(() => {
     const total = hunks.length;
@@ -534,6 +561,10 @@ export const ReviewPanel: React.FC<ReviewPanelProps> = ({
         // Mark selected hunk as unread
         e.preventDefault();
         handleMarkAsUnread(selectedHunkId);
+      } else if (matchesKeybind(e, KEYBINDS.MARK_FILE_READ)) {
+        // Mark entire file (all hunks) as read
+        e.preventDefault();
+        handleMarkFileAsRead(selectedHunkId);
       } else if (matchesKeybind(e, KEYBINDS.TOGGLE_HUNK_COLLAPSE)) {
         // Toggle expand/collapse state of selected hunk
         e.preventDefault();
@@ -553,6 +584,7 @@ export const ReviewPanel: React.FC<ReviewPanelProps> = ({
     handleToggleRead,
     handleMarkAsRead,
     handleMarkAsUnread,
+    handleMarkFileAsRead,
   ]);
 
   // Global keyboard shortcuts (Ctrl+R / Cmd+R for refresh, Ctrl+F / Cmd+F for search)

src/utils/ui/keybinds.ts

@@ -276,6 +276,9 @@ export const KEYBINDS = {
   /** Mark selected hunk as unread in Code Review panel */
   MARK_HUNK_UNREAD: { key: "h" },
 
+  /** Mark entire file (all hunks) as read in Code Review panel */
+  MARK_FILE_READ: { key: "M", shift: true },
+
   /** Toggle hunk expand/collapse in Code Review panel */
   TOGGLE_HUNK_COLLAPSE: { key: " " },
 } as const;