fix: CRITICAL - Store pipelines in BOTH session.pipelines_history AND pipelines collection

- Root cause: GET /pipelines reads from pipelines collection
- But _create_pipeline_record only wrote to session.pipelines_history
- Solution: Call pipeline_manager.create_pipeline_metadata() too
- Also updated _update_pipeline_status to update both locations
- Pipelines now appear in GET /sessions/{id}/pipelines endpoint
- Fixes empty pipelines array issue

api_routes_v2.py

@@ -259,14 +259,30 @@ def _create_pipeline_record(
         "model_provider": pipeline_def.get("_model_provider"), # To be filled during execution
         "model_name": pipeline_def.get("_model"), 
         "pipeline_s3_key": s3_key,
-        # Preview fields allowed in metadata
         "result_preview": None 
     }
     
+    # V3 CRITICAL: Update session.pipelines_history
     current_session = session_manager.get_session(session_id) or {}
     hist = list(current_session.get("pipelines_history", []))
     hist.insert(0, pipeline_meta)
     session_manager.update_session(session_id, {"pipelines_history": hist})
+    
+    # V3 CRITICAL: Also create record in pipelines collection (for GET /pipelines endpoint)
+    try:
+        from services.pipeline_manager import get_pipeline_manager
+        pipeline_mgr = get_pipeline_manager()
+        pipeline_mgr.create_pipeline_metadata(
+            pipeline_id=pipeline_id,
+            session_id=session_id,
+            pipeline_name=pipeline_def.get("pipeline_name", "Untitled"),
+            s3_key=s3_key,
+            status=status,
+            created_by_message=""
+        )
+    except Exception as e:
+        print(f"Warning: Failed to create pipelines collection record: {e}")
+        # Don't fail the whole operation if this fails
 
     return pipeline_id
 
@@ -318,6 +334,17 @@ def _update_pipeline_status(pipeline_id: str, session_id: str, status: str, resu
                             p["result_preview"] = text[:500]
                     break
             session_manager.update_session(session_id, {"pipelines_history": hist})
+            
+        # 3. Also update pipelines collection (for GET /pipelines endpoint)
+        try:
+            from services.pipeline_manager import get_pipeline_manager
+            pipeline_mgr = get_pipeline_manager()
+            pipeline_mgr.update_pipeline_status(
+                pipeline_id=pipeline_id,
+                status=status
+            )
+        except Exception as e:
+            print(f"Warning: Failed to update pipelines collection: {e}")
     except Exception:
         pass