fix: correct path handling in vim atomic write tests

The vim atomic write tests were failing because they passed absolute paths
to handle_changes(), but the watch service expects relative paths (it converts
absolute paths from the file watcher to relative paths internally).

Fixed by converting absolute paths to relative paths in test setup to match
the actual watch service behavior.

Co-authored-by: Paul Hernandez <phernandez@users.noreply.github.com>

Author: claude[bot]

tests/sync/test_watch_service_edge_cases.py

@@ -103,7 +103,9 @@ async def test_handle_vim_atomic_write_delete_still_exists(watch_service, projec
     test_file.write_text(modified_content)
 
     # Setup DELETE event even though file still exists (vim's atomic write behavior)
-    changes = {(Change.deleted, str(test_file))}
+    # Use relative path like the real watch service would
+    relative_path = str(test_file.relative_to(project_dir))
+    changes = {(Change.deleted, relative_path)}
 
     # Handle the change
     await watch_service.handle_changes(test_project, changes)
@@ -153,9 +155,12 @@ async def test_handle_true_deletion_vs_vim_atomic(watch_service, project_config,
     delete_file.unlink()
 
     # Setup DELETE events for both files
+    # Use relative paths like the real watch service would
+    atomic_relative = str(atomic_file.relative_to(project_dir))
+    delete_relative = str(delete_file.relative_to(project_dir))
     changes = {
-        (Change.deleted, str(atomic_file)),  # File still exists - atomic write
-        (Change.deleted, str(delete_file)),  # File deleted - true deletion
+        (Change.deleted, atomic_relative),  # File still exists - atomic write
+        (Change.deleted, delete_relative),  # File deleted - true deletion
     }
 
     # Handle the changes
@@ -230,7 +235,9 @@ async def test_handle_vim_atomic_write_markdown_with_relations(watch_service, pr
     main_file.write_text(modified_content)
 
     # Setup DELETE event (vim atomic write)
-    changes = {(Change.deleted, str(main_file))}
+    # Use relative path like the real watch service would
+    relative_path = str(main_file.relative_to(project_dir))
+    changes = {(Change.deleted, relative_path)}
 
     # Handle the change
     await watch_service.handle_changes(test_project, changes)
@@ -260,7 +267,9 @@ async def test_handle_vim_atomic_write_directory_path_ignored(watch_service, pro
     test_dir.mkdir()
 
     # Setup DELETE event for directory (should be ignored)
-    changes = {(Change.deleted, str(test_dir))}
+    # Use relative path like the real watch service would
+    relative_path = str(test_dir.relative_to(project_dir))
+    changes = {(Change.deleted, relative_path)}
 
     # Handle the change - should not cause errors
     await watch_service.handle_changes(test_project, changes)