fix: turn duplicate emulator action into go-to

Co-authored-by: Orca <help@stably.ai>

src/renderer/src/components/tab-bar/TabBar.context-menu.test.ts

@@ -423,7 +423,7 @@ describe('TabBar context menu wiring', () => {
     expect(menuLabels[3]).toContain('New Browser Tab')
   })
 
-  it('disables New Mobile Emulator when the workspace already has one', async () => {
+  it('turns New Mobile Emulator into a go-to action when the workspace already has one', async () => {
     const onNewSimulatorTab = vi.fn()
     appStoreSnapshot.unifiedTabsByWorktree = {
       'wt-1': [
@@ -449,13 +449,19 @@ describe('TabBar context menu wiring', () => {
     })
 
     const emulatorItem = findChildrenByType(element, 'DropdownMenuItem').find((item) =>
-      extractText(item.props.children).includes('New Mobile Emulator')
+      extractText(item.props.children).includes('Go to Mobile Emulator')
     )
-    expect(emulatorItem?.props.disabled).toBe(true)
-    expect(emulatorItem?.props.onSelect).toBeUndefined()
+    expect(emulatorItem).toBeTruthy()
+    if (!emulatorItem) {
+      throw new Error('Go to Mobile Emulator menu item not rendered')
+    }
+    expect(emulatorItem.props.disabled).toBeUndefined()
+    expect(emulatorItem.props.onSelect).toBeTypeOf('function')
+    ;(emulatorItem.props.onSelect as () => void)()
+    expect(onNewSimulatorTab).toHaveBeenCalledTimes(1)
 
     const tooltip = findChildrenByType(element, 'TooltipContent').find((item) =>
-      extractText(item.props.children).includes('An emulator already exists in this workspace.')
+      extractText(item.props.children).includes('Open the existing emulator tab.')
     )
     expect(tooltip).toBeTruthy()
   })

src/renderer/src/components/tab-bar/TabBar.tsx

@@ -63,7 +63,6 @@ type GitStatusEntries = ReturnType<typeof useAppStore.getState>['gitStatusByWork
 const EMPTY_GIT_STATUS_ENTRIES: GitStatusEntries = []
 const EMPTY_AGENT_CMD_OVERRIDES: Partial<Record<TuiAgent, string>> = {}
 const EMPTY_UNIFIED_TABS: readonly Tab[] = []
-const EMULATOR_EXISTS_TOOLTIP = 'An emulator already exists in this workspace.'
 
 type TabBarProps = {
   tabs: (TerminalTab & { unifiedTabId?: string })[]
@@ -498,19 +497,17 @@ function TabBarInner({
       workspaceHasSimulatorTab ? (
         <Tooltip>
           <TooltipTrigger asChild>
-            <span className="block">
-              <DropdownMenuItem
-                disabled
-                className="gap-2 rounded-[7px] px-2 py-1.5 text-[12px] leading-5 font-medium"
-              >
-                <Smartphone className="size-4 text-muted-foreground" />
-                New Mobile Emulator
-                <DropdownMenuShortcut>{newSimulatorShortcut}</DropdownMenuShortcut>
-              </DropdownMenuItem>
-            </span>
+            <DropdownMenuItem
+              onSelect={onNewSimulatorTab}
+              className="gap-2 rounded-[7px] px-2 py-1.5 text-[12px] leading-5 font-medium"
+            >
+              <Smartphone className="size-4 text-muted-foreground" />
+              Go to Mobile Emulator
+              <DropdownMenuShortcut>{newSimulatorShortcut}</DropdownMenuShortcut>
+            </DropdownMenuItem>
           </TooltipTrigger>
           <TooltipContent side="right" sideOffset={8} className="z-[80]">
-            {EMULATOR_EXISTS_TOOLTIP}
+            Open the existing emulator tab.
           </TooltipContent>
         </Tooltip>
       ) : (

src/renderer/src/components/tab-group/useTabGroupWorkspaceModel.ts

@@ -26,6 +26,7 @@ import {
 import { closeTerminalTab } from '../terminal/terminal-tab-actions'
 import { openTabBarEntry, type TabCreateEntryArgs } from '../tab-bar/tab-create-entry-action'
 import { openMobileEmulatorTab } from '@/lib/open-mobile-emulator-tab'
+import { ensureSimulatorTab, getSimulatorTabForWorktree } from '@/lib/ensure-simulator-tab'
 
 export function recordTerminalTabGroupSplit(createdTerminal: TerminalTab | null | undefined): void {
   if (!createdTerminal) {
@@ -577,8 +578,11 @@ export function useTabGroupWorkspaceModel({
       },
       newSimulatorTab: worktreeState.mobileEmulatorEnabled
         ? () => {
+            if (getSimulatorTabForWorktree(worktreeId)) {
+              void ensureSimulatorTab(worktreeId, { surfacePane: true })
+              return
+            }
             // Why: mobile simulators are most useful beside the current tab group.
-            // Re-open is guarded as a no-op once a worktree emulator tab exists.
             void openMobileEmulatorTab(worktreeId, {
               placement: 'rightSplit',
               targetGroupId: groupId