fix(tests): add iCloud mocks to all test files and address code review feedback

- Add _should_upload_to_icloud mock to test_coverage_uploads_notification.py
  (_all_should_upload_false helper + 3 inline patch blocks)
- Add cfg.icloud_username/password = None to all onboarding test mocks
- Add iCloud creds to fully-configured onboarding test
- Fix noqa comment accuracy (unofficial third-party, not first-party)
- Replace generic Exception with RuntimeError in upload error handler

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

app/tasks/upload_to_icloud.py

@@ -59,7 +59,7 @@ def _get_icloud_api(
         ImportError: If ``pyicloud`` is not installed.
         ValueError: If authentication fails or 2FA is required interactively.
     """
-    from pyicloud import PyiCloudService  # noqa: S404 – trusted first-party usage
+    from pyicloud import PyiCloudService  # noqa: S404 – unofficial third-party iCloud client
 
     kwargs: dict = {}
     if cookie_directory:
@@ -174,4 +174,4 @@ def upload_to_icloud(self, file_path: str, file_id: int = None, folder_override:
         error_msg = f"Error uploading {filename} to iCloud Drive: {e}"
         logger.error(f"[{task_id}] {error_msg}")
         log_task_progress(task_id, "upload_to_icloud", "failure", error_msg, file_id=file_id)
-        raise Exception(error_msg) from e
+        raise RuntimeError(error_msg) from e