fix(diff): reload a combined section after save so a stale original side recovers

A revalidation rejected while a row was dirty was never re-driven: requestSectionReload
refuses while dirty, and the git-status signature does not change for an edit inside an
already-modified line, so the original side stayed stale indefinitely.

src/renderer/src/components/editor/combined-diff/CombinedDiffViewer.tsx

@@ -203,6 +203,7 @@ export default function CombinedDiffViewer({
     isAllMode: entrySet.isAllMode,
     isBranchMode: entrySet.isBranchMode,
     isCommitMode: entrySet.isCommitMode,
+    requestSectionReloadRef: registry.requestSectionReloadRef,
     sectionsRef: registry.sectionsRef,
     setSectionHeights,
     setSections

src/renderer/src/components/editor/combined-diff/review-controls/use-combined-diff-section-actions.ts

@@ -26,6 +26,7 @@ export function useCombinedDiffSectionActions({
   isAllMode,
   isBranchMode,
   isCommitMode,
+  requestSectionReloadRef,
   sectionsRef,
   setSectionHeights,
   setSections
@@ -38,6 +39,7 @@ export function useCombinedDiffSectionActions({
   isAllMode: boolean
   isBranchMode: boolean
   isCommitMode: boolean
+  requestSectionReloadRef: React.RefObject<(index: number) => void>
   sectionsRef: React.RefObject<DiffSection[]>
   setSectionHeights: React.Dispatch<React.SetStateAction<Record<number, number>>>
   setSections: React.Dispatch<React.SetStateAction<DiffSection[]>>
@@ -144,6 +146,7 @@ export function useCombinedDiffSectionActions({
 
   const handleSectionSaveRef = useCombinedDiffSectionSave({
     file,
+    requestSectionReloadRef,
     sectionsRef,
     setSectionHeights,
     setSections

src/renderer/src/components/editor/combined-diff/review-controls/use-combined-diff-section-save.test.tsx

@@ -44,11 +44,18 @@ function section(key = 'file.ts'): DiffSection {
     }
   }
 }
+const reloadSpy = vi.fn()
 function setup(initial = [section()]) {
   return renderHook(() => {
     const { sections, setSections, sectionsRef } = useCombinedDiffSectionsState(initial)
     const [heights, setSectionHeights] = useState<Record<number, number>>({ 0: 100, 1: 200 })
-    const save = useCombinedDiffSectionSave({ file, sectionsRef, setSections, setSectionHeights })
+    const save = useCombinedDiffSectionSave({
+      file,
+      requestSectionReloadRef: { current: reloadSpy },
+      sectionsRef,
+      setSections,
+      setSectionHeights
+    })
     return { sections, setSections, heights, save }
   })
 }
@@ -216,3 +223,13 @@ describe('combined diff section saves', () => {
     expect(writeFile).not.toHaveBeenCalled()
   })
 })
+
+it('re-drives a reload after saving, so a revalidation rejected while dirty is not stranded', async () => {
+  const { result } = setup()
+  await act(async () => {
+    await result.current.save.current(0)
+  })
+  // The git-status signature does not change for an edit inside an already-modified line, so the
+  // save is the only event that can recover a stale original side.
+  expect(reloadSpy).toHaveBeenCalledWith(0)
+})

src/renderer/src/components/editor/combined-diff/review-controls/use-combined-diff-section-save.ts

@@ -43,11 +43,13 @@ function acknowledgeSectionSave(section: DiffSection, content: string): DiffSect
 
 export function useCombinedDiffSectionSave({
   file,
+  requestSectionReloadRef,
   sectionsRef,
   setSectionHeights,
   setSections
 }: {
   file: OpenFile
+  requestSectionReloadRef: React.RefObject<(index: number) => void>
   sectionsRef: React.RefObject<DiffSection[]>
   setSectionHeights: React.Dispatch<React.SetStateAction<Record<number, number>>>
   setSections: React.Dispatch<React.SetStateAction<DiffSection[]>>
@@ -95,6 +97,10 @@ export function useCombinedDiffSectionSave({
                 : entry
             )
           )
+          // Why: a revalidation rejected while this row was dirty left the original side stale,
+          // and the git-status signature does not change for an edit inside an already-modified
+          // line, so nothing else re-drives it. The row is clean now, so the reload can proceed.
+          requestSectionReloadRef.current(savedIndex)
         })
         .catch((error: unknown) => {
           console.error('Save failed:', error)
@@ -107,7 +113,7 @@ export function useCombinedDiffSectionSave({
       saves.set(key, tracked)
       return tracked
     },
-    [file, sectionsRef, setSectionHeights, setSections]
+    [file, requestSectionReloadRef, sectionsRef, setSectionHeights, setSections]
   )
   const saveRef = useRef(saveSection)
   useLayoutEffect(() => {