fix(menu): restore paste in macOS native dialogs (#12645)

* fix(menu): restore paste in macOS native dialogs

* test(menu): pin platform for paste routing coverage

CI runs unit shards on ubuntu-latest only, so the unpinned paste-routing
test asserted "no native paste" vacuously: a double-route regression
passed green on Linux. Cover darwin/linux/win32 explicitly so the
exactly-once contract holds on every platform, and assert the item exists
in the negative-only cases so a rename cannot pass them silently.

Also document why the native first-responder fallback exists.

---------

Co-authored-by: Jinwoo-H <Jinwoo-H@users.noreply.github.com>

src/main/menu/register-app-menu.test.ts

@@ -1,9 +1,15 @@
-import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 
-const { buildFromTemplateMock, setApplicationMenuMock, getFocusedWindowMock } = vi.hoisted(() => ({
+const {
+  buildFromTemplateMock,
+  setApplicationMenuMock,
+  getFocusedWindowMock,
+  sendActionToFirstResponderMock
+} = vi.hoisted(() => ({
   buildFromTemplateMock: vi.fn(),
   setApplicationMenuMock: vi.fn(),
-  getFocusedWindowMock: vi.fn()
+  getFocusedWindowMock: vi.fn(),
+  sendActionToFirstResponderMock: vi.fn()
 }))
 
 vi.mock('electron', () => ({
@@ -12,7 +18,8 @@ vi.mock('electron', () => ({
   },
   Menu: {
     buildFromTemplate: buildFromTemplateMock,
-    setApplicationMenu: setApplicationMenuMock
+    setApplicationMenu: setApplicationMenuMock,
+    sendActionToFirstResponder: sendActionToFirstResponderMock
   },
   app: {
     name: 'Orca'
@@ -70,9 +77,14 @@ describe('registerAppMenu', () => {
     buildFromTemplateMock.mockReset()
     setApplicationMenuMock.mockReset()
     getFocusedWindowMock.mockReset()
+    sendActionToFirstResponderMock.mockReset()
     buildFromTemplateMock.mockImplementation((template) => ({ template }))
   })
 
+  afterEach(() => {
+    vi.restoreAllMocks()
+  })
+
   it('shows reload shortcuts as policy-routed menu hints', () => {
     registerAppMenu(buildMenuOptions())
 
@@ -214,23 +226,59 @@ describe('registerAppMenu', () => {
     expect(paletteItem?.accelerator).toBeUndefined()
   })
 
-  it('routes Edit > Paste through Orca coordinated paste ownership', () => {
-    const send = vi.fn()
-    getFocusedWindowMock.mockReturnValue({ webContents: { send } })
+  // Why: pin the platform on every case — CI runs this suite on Linux only, so an
+  // unpinned test leaves the other platforms' branches entirely uncovered.
+  it.each(['darwin', 'linux', 'win32'] as const)(
+    'routes Edit > Paste through Orca coordinated paste ownership on %s',
+    (platform) => {
+      vi.spyOn(process, 'platform', 'get').mockReturnValue(platform)
+      const send = vi.fn()
+      getFocusedWindowMock.mockReturnValue({ webContents: { send } })
+      registerAppMenu(buildMenuOptions())
+
+      const editSubmenu = getSubmenu(getTemplate(), 'Edit')
+      const pasteItem = editSubmenu.find((item) => item.label === 'Paste')
+
+      expect(pasteItem).toBeDefined()
+      expect(pasteItem?.role).toBeUndefined()
+      expect(pasteItem?.accelerator).toBe('CmdOrCtrl+V')
+
+      pasteItem?.click?.({} as never, {} as never, {} as never)
+
+      expect(send).toHaveBeenCalledOnce()
+      expect(send).toHaveBeenCalledWith('ui:appMenuPaste')
+      expect(sendActionToFirstResponderMock).not.toHaveBeenCalled()
+    }
+  )
+
+  it('routes Edit > Paste to the native first responder once on macOS without a focused window', () => {
+    vi.spyOn(process, 'platform', 'get').mockReturnValue('darwin')
+    getFocusedWindowMock.mockReturnValue(null)
     registerAppMenu(buildMenuOptions())
 
-    const editSubmenu = getSubmenu(getTemplate(), 'Edit')
-    const pasteItem = editSubmenu.find((item) => item.label === 'Paste')
-
-    expect(pasteItem).toBeDefined()
-    expect(pasteItem?.role).toBeUndefined()
-    expect(pasteItem?.accelerator).toBe('CmdOrCtrl+V')
-
+    const pasteItem = getSubmenu(getTemplate(), 'Edit').find((item) => item.label === 'Paste')
     pasteItem?.click?.({} as never, {} as never, {} as never)
 
-    expect(send).toHaveBeenCalledWith('ui:appMenuPaste')
+    expect(sendActionToFirstResponderMock).toHaveBeenCalledOnce()
+    expect(sendActionToFirstResponderMock).toHaveBeenCalledWith('paste:')
   })
 
+  it.each(['linux', 'win32'] as const)(
+    'does not invoke the native paste responder on %s without a focused window',
+    (platform) => {
+      vi.spyOn(process, 'platform', 'get').mockReturnValue(platform)
+      getFocusedWindowMock.mockReturnValue(null)
+      registerAppMenu(buildMenuOptions())
+
+      const pasteItem = getSubmenu(getTemplate(), 'Edit').find((item) => item.label === 'Paste')
+      // Why: this case asserts only a negative, so it would pass green if the item vanished.
+      expect(pasteItem).toBeDefined()
+      pasteItem?.click?.({} as never, {} as never, {} as never)
+
+      expect(sendActionToFirstResponderMock).not.toHaveBeenCalled()
+    }
+  )
+
   it.runIf(!isMac)('puts Settings and Exit under File on Windows/Linux', () => {
     registerAppMenu(buildMenuOptions())
 

src/main/menu/register-app-menu.ts

@@ -180,7 +180,17 @@ function buildAndApplyMenu(options: RegisterAppMenuOptions): void {
         click: () => {
           // Why: a focused terminal/native-chat pane is not a native editable
           // control, so raw Electron paste cannot know which Orca surface owns it.
-          BrowserWindow.getFocusedWindow()?.webContents.send('ui:appMenuPaste')
+          const focusedWindow = BrowserWindow.getFocusedWindow()
+          if (focusedWindow) {
+            focusedWindow.webContents.send('ui:appMenuPaste')
+            return
+          }
+
+          // Why: a macOS native panel (open/save, Go to Folder) leaves no focused
+          // BrowserWindow, so overriding the paste role would strand Cmd+V as a no-op.
+          if (isMac) {
+            Menu.sendActionToFirstResponder('paste:')
+          }
         }
       },
       { role: 'selectAll' }