Handle blur race when file changes during rename

When switching files mid-rename, React may deliver the old input's
blur event after the new file renders, causing a stale rename commit.

Mark the rename as cancelled when the active file changes, and add
test coverage verifying stale blur events are ignored.

src/renderer/src/components/editor/EditorPanelHeaderPath.test.tsx

@@ -196,7 +196,8 @@ describe('EditorPanelHeaderPath inline rename', () => {
     const rerenderPath = renderPath(baseFile())
     openRenameInput()
 
-    fireEvent.change(getRenameInput('Rename file notes.md'), { target: { value: 'renamed.md' } })
+    const input = getRenameInput('Rename file notes.md')
+    fireEvent.change(input, { target: { value: 'renamed.md' } })
     rerenderPath(
       baseFile({
         id: '/repo/other.md',
@@ -207,6 +208,9 @@ describe('EditorPanelHeaderPath inline rename', () => {
 
     expect(screen.queryByLabelText('Rename file notes.md')).toBeNull()
     expect(screen.queryByLabelText('Rename file other.md')).toBeNull()
+
+    // React may deliver the removed input's blur after the active file render.
+    fireEvent.blur(input)
     expect(renameFileOnDiskMock).not.toHaveBeenCalled()
   })
 

src/renderer/src/components/editor/editor-header-file-rename.ts

@@ -30,6 +30,7 @@ export function useEditorHeaderFileRename(activeFile: OpenFile): EditorHeaderFil
   // Why: the header renders one unkeyed path strip for every file, so a file
   // switch mid-rename would otherwise commit the typed name against the new path.
   if (renameFilePath !== activeFile.filePath) {
+    renameCancelledRef.current = true
     setRenameFilePath(activeFile.filePath)
     setIsRenaming(false)
   }