fix(#4581): restore hidden Cancel button in showPromptDialog after a hideCancel confirm

Codex gate (SILENT): the new outside-symlink info dialog uses showConfirmDialog({hideCancel:true})
which sets the shared #appDialogCancel to display:none; showPromptDialog only reset textContent, so a
later rename/new-file prompt opened with no Cancel button. Fix: showPromptDialog now restores
cancelBtn.style.display='' first. + regression test.

static/ui.js

@@ -5918,7 +5918,13 @@ function showPromptDialog(opts={}){
     input.value=prefill;input.placeholder=opts.placeholder||'';
     input.autocomplete='off';input.spellcheck=false;
   }
-  if(cancelBtn) cancelBtn.textContent=opts.cancelLabel||t('cancel');
+  if(cancelBtn){
+    // A prior showConfirmDialog({hideCancel:true}) (e.g. the outside-symlink info
+    // dialog, #4581) may have hidden the shared Cancel button; always restore it
+    // so a subsequent prompt keeps its Cancel affordance.
+    cancelBtn.style.display='';
+    cancelBtn.textContent=opts.cancelLabel||t('cancel');
+  }
   if(confirmBtn){
     confirmBtn.textContent=opts.confirmLabel||t('create');
     confirmBtn.classList.toggle('danger',!!opts.danger);

tests/test_workspace_context_menu_and_rename.py

@@ -184,6 +184,20 @@ class ShowPromptDialogPrefillTests(unittest.TestCase):
                     break
         return self.src[start:end]
 
+    def test_show_prompt_dialog_restores_hidden_cancel_button(self):
+        """#4581: the outside-symlink info dialog calls showConfirmDialog with
+        hideCancel:true, which sets the shared #appDialogCancel button to
+        display:none. showPromptDialog reuses the same button, so it must restore
+        the display before showing — otherwise the next rename/new-file prompt
+        opens with no Cancel button after a user clicks an external symlink."""
+        body = self._slice_show_prompt_dialog()
+        self.assertIn(
+            "cancelBtn.style.display=''", body.replace(" ", ""),
+            "showPromptDialog must reset cancelBtn.style.display so a prior "
+            "showConfirmDialog({hideCancel:true}) can't leave the Cancel button "
+            "hidden on a subsequent prompt (#4581 regression).",
+        )
+
     def test_show_prompt_dialog_accepts_default_value_alias(self):
         body = self._slice_show_prompt_dialog()
         # Must reference `opts.defaultValue` somewhere — the alias was the