fix(test): mock create_pr at save_loading import, not github_client internals

The e2e test was patching edit_python_pe.github_client._commit_and_push
which is a private function deep inside create_pr. Python's patch() replaces
names in the module where they are looked up, so patching the original
definition site has no effect when the caller (save_loading.py) has already
imported create_pr as a bound reference.

The correct target is edit_python_pe.screens.save_loading.create_pr, which
is the name actually resolved at call time. With the wrong patch target,
create_pr executed against the real filesystem, raised an exception inside
the perform_save() thread, and the screen never transitioned to
SaveLoadingScreen.

Also:
- Add await pilot.pause() before clicking Save to allow reactive value
  assignments to propagate through the Textual event loop first
- Simplify mock setup: one mock_create_pr replaces four separate mocks

Author: zodiacfireworks

tests/e2e/test_app_e2e.py

@@ -15,34 +15,26 @@ class TestAppE2E:
     @pytest.mark.asyncio
     @patch("edit_python_pe.screens.loading.get_repo")
     @patch("edit_python_pe.screens.loading.fork_repo")
-    @patch("edit_python_pe.github_client._commit_and_push")
+    @patch("edit_python_pe.screens.save_loading.create_pr")
     @patch("keyring.get_password", return_value=None)
     @patch("keyring.set_password")
     async def test_full_app_flow(
         self,
         mock_set_password,
         mock_get_password,
-        mock_commit_and_push,
+        mock_create_pr,
         mock_fork_repo,
         mock_get_repo_loading,
     ):
         mock_repo = MagicMock()
         mock_forked = MagicMock()
         mock_get_repo_loading.return_value = ("fake-token", mock_repo)
         mock_fork_repo.return_value = (tempfile.gettempdir(), mock_forked)
-        mock_commit_and_push.return_value = (
-            "Commit message",
-            MagicMock(),
-            MagicMock(),
-            MagicMock(),
+        mock_create_pr.return_value = (
+            "Woohoo! john_doe-abc12345.md was saved successfully and your new PR is ready! 🎉",
+            "https://github.com/fake/pr",
         )
 
-        # Create a mock PR
-        mock_pr = MagicMock()
-        mock_pr.html_url = "https://github.com/fake/pr"
-        mock_repo.get_pulls.return_value = []
-        mock_repo.create_pull.return_value = mock_pr
-
         app = MemberApp()
         async with app.run_test(size=(120, 100)) as pilot:
             # 1. Language Screen
@@ -108,6 +100,7 @@ async def test_full_app_flow(
                     -1
                 ].url_input.value = "https://github.com/john"
 
+            await pilot.pause()
             await pilot.click("#member-form-save")
 
             # 6. Save Loading Screen — give up to 5 s for the background work