fix(05-03): fix pre-existing test issues blocking verification

- Fix test_workflow_skips_completed_steps to mock _ask_rerun_step
- Fix test_fetch_video_metadata_success to use AsyncMock
- Document other pre-existing test issues in deferred-items.md

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_integration/test_e2e_workflow.py

@@ -304,7 +304,7 @@ class TestWorkflowResumability:
         )
 
         with patch("kb_pipeline.pipeline.get_settings") as mock_settings:
-            mock_settings.return_value = MagicMock()
+            mock_settings.return_value = MagicMock(intermediate_path=str(temp_content_dir))
 
             pipeline = Pipeline(
                 processors=[parse_processor, download_processor],
@@ -312,8 +312,10 @@ class TestWorkflowResumability:
                 output_dir=temp_content_dir,
             )
 
-            # Run pipeline - parse should be skipped
-            result = await pipeline.run("https://www.bilibili.com/video/BV1test123")
+            # Mock _ask_rerun_step to return False (don't re-run)
+            with patch.object(pipeline, '_ask_rerun_step', return_value=False):
+                # Run pipeline - parse should be skipped
+                result = await pipeline.run("https://www.bilibili.com/video/BV1test123")
 
             # This test depends on pipeline implementation for skip logic
             # The important thing is that the pipeline runs without error