feat: Complete API response corrections - add pipelines endpoint and enhanced error handling

- Added GET /api/v2/sessions/{session_id}/pipelines endpoint
- Returns all pipeline executions with full component details
- Includes component_id, status, output, errors, metadata
- Removes internal S3 keys from response

- Enhanced pipeline completion responses
- Added output_id and download_url to final_output
- Enables direct download of pipeline results

- Improved error handling
- Added component-level error details in error responses
- Includes failed_component with component_id, tool_name, and error
- Better debugging and UI error display

All API corrections from specification now fully implemented.

api_routes_v2.py

@@ -963,6 +963,55 @@ async def delete_session(session_id: str):
          
     return {"status": "deleted", "session_id": session_id}
 
+@router.get("/sessions/{session_id}/pipelines", response_model=Dict[str, Any])
+async def get_session_pipelines(session_id: str):
+    """
+    Get all pipeline executions for a session with full component details
+    """
+    try:
+        from services.pipeline_manager import get_pipeline_manager
+        pipeline_mgr = get_pipeline_manager()
+        
+        # Get all pipelines for this session from pipeline_manager
+        pipelines = pipeline_mgr.get_session_pipelines(session_id, limit=100)
+        
+        # Process each pipeline to add component details and remove internal fields
+        enhanced_pipelines = []
+        for pipeline in pipelines:
+            enhanced_pipe = pipeline.copy()
+            
+            # Rename result_preview to result if present
+            if "result_preview" in enhanced_pipe:
+                enhanced_pipe["result"] = enhanced_pipe.pop("result_preview")
+            
+            # Remove internal S3 keys
+            enhanced_pipe.pop("pipeline_s3_key", None)
+            enhanced_pipe.pop("pipeline_definition_s3_key", None)
+            
+            # Add hasError if not present
+            if "hasError" not in enhanced_pipe:
+                enhanced_pipe["hasError"] = enhanced_pipe.get("status") == "failed"
+            
+            # Ensure final_output_url is included (presigned URL)
+            if "final_output_presigned_url" in enhanced_pipe:
+                enhanced_pipe["final_output_url"] = enhanced_pipe["final_output_presigned_url"]
+            
+            # Components are already in the correct format from pipeline_manager
+            # They include: component_id, status, component_output, hasError, error, metadata
+            
+            enhanced_pipelines.append(enhanced_pipe)
+        
+        return {
+            "session_id": session_id,
+            "pipelines": enhanced_pipelines
+        }
+        
+    except Exception as e:
+        raise HTTPException(
+            status_code=500,
+            detail=f"Error retrieving pipelines: {str(e)}"
+        )
+
 # ========================
 # UNIFIED CHAT (non-streaming)
 # ========================
@@ -1151,7 +1200,18 @@ async def chat_unified(
                 result_text = _extract_user_facing_text(result)
                 friendly = f"🎉 Pipeline completed successfully!"
                 output = {"component_summary": "Pipeline executed successfully", "steps": len(proposed.get("pipeline_steps", proposed.get("components", [])))}
-                final_output = {"text": result_text, "result": result}
+                final_output = {"text": result_text}
+                # Add output_id and download_url from pipeline_manager
+                if pipeline_id:
+                    try:
+                        from services.pipeline_manager import get_pipeline_manager
+                        pipeline_mgr = get_pipeline_manager()
+                        pipeline_record = pipeline_mgr.get_pipeline(pipeline_id)
+                        if pipeline_record:
+                            final_output["output_id"] = pipeline_record.get("output_id")
+                            final_output["download_url"] = pipeline_record.get("final_output_presigned_url")
+                    except Exception as e:
+                        print(f"Warning: Could not get output_id/download_url: {e}")
                 
                 api_data = {
                     "type": "pipeline_completed",
@@ -1172,8 +1232,35 @@ async def chat_unified(
                 pipeline_id = proposed.get("pipeline_id")
                 if pipeline_id:
                     _update_pipeline_status(pipeline_id, chat_id, "failed", result={"error": str(e)})
+                
+                # Get component-level error details
+                failed_component = None
+                if pipeline_id:
+                    try:
+                        from services.pipeline_manager import get_pipeline_manager
+                        pipeline_mgr = get_pipeline_manager()
+                        pipeline_record = pipeline_mgr.get_pipeline(pipeline_id)
+                        if pipeline_record and pipeline_record.get("components"):
+                            # Find first failed component
+                            for comp in pipeline_record.get("components", []):
+                                if comp.get("hasError") or comp.get("status") == "failed":
+                                    failed_component = {
+                                        "component_id": comp.get("component_id"),
+                                        "tool_name": comp.get("component_name"),
+                                        "error": comp.get("error")
+                                    }
+                                    break
+                    except Exception as comp_error:
+                        print(f"Warning: Could not get component error details: {comp_error}")
+                
                 friendly = f"❌ Pipeline execution failed: {str(e)}"
-                api_data = {"type": "error", "error_code": "PIPELINE_EXECUTION_FAILED", "message": str(e)}
+                api_data = {
+                    "type": "error",
+                    "error_code": "PIPELINE_EXECUTION_FAILED",
+                    "message": str(e)
+                }
+                if failed_component:
+                    api_data["failed_component"] = failed_component
                 return _assistant_response_payload(
                     chat_id=chat_id,
                     friendly_response=friendly,