fix: Filter non-serializable objects in pipeline metadata

- Skip CharacterMemory and callback functions during serialization
- Add .pids/ and .serena/ to gitignore
- Add workflow integration documentation

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

pixelle_video/pipelines/standard.py

@@ -495,11 +495,26 @@ class StandardPipeline(LinearVideoPipeline):
                 logger.warning("No task_id in storyboard, skipping persistence")
                 return
             
-            # Build metadata
-            input_with_title = ctx.params.copy()
-            input_with_title["text"] = ctx.input_text # Ensure text is included
-            if not input_with_title.get("title"):
-                input_with_title["title"] = storyboard.title
+            # Build metadata - filter out non-serializable objects
+            clean_input = {}
+            for key, value in ctx.params.items():
+                # Skip non-serializable objects like CharacterMemory
+                if key == "character_memory":
+                    # Convert to serializable dict if present
+                    if value is not None and hasattr(value, 'to_dict'):
+                        clean_input["character_memory"] = value.to_dict()
+                elif key == "progress_callback":
+                    # Skip callback functions
+                    continue
+                elif callable(value):
+                    # Skip any callable objects
+                    continue
+                else:
+                    clean_input[key] = value
+            
+            clean_input["text"] = ctx.input_text  # Ensure text is included
+            if not clean_input.get("title"):
+                clean_input["title"] = storyboard.title
             
             metadata = {
                 "task_id": task_id,
@@ -507,7 +522,7 @@ class StandardPipeline(LinearVideoPipeline):
                 "completed_at": storyboard.completed_at.isoformat() if storyboard.completed_at else None,
                 "status": "completed",
                 
-                "input": input_with_title,
+                "input": clean_input,
                 
                 "result": {
                     "video_path": result.video_path,