fix: update progress callback and event types for workflow execution

- Changed progress callback from "execution_complete" to "workflow_graph_finished" to provide intermediate updates.
- Updated documentation to clarify the distinction between "workflow_graph_finished" and "execution_complete".
- Adjusted frontend API handling to accommodate new event structure and ensure proper result serialization.

backend/routers/prompts.py

@@ -275,7 +275,8 @@ async def execute_unified_prompt_stream(
     Returns live progress updates during workflow execution:
     - execution_started: Workflow has begun
     - node_complete: Each node completes
-    - execution_complete: Final result ready
+    - workflow_graph_finished: Workflow-Graph fertig (Zwischen-Info, kein Endergebnis)
+    - execution_complete: Endergebnis (wie POST /execute, Feld result)
     - execution_failed: Error occurred
 
     Use this endpoint for long-running workflows (>30s) to avoid gateway timeouts.
@@ -364,6 +365,20 @@ async def execute_unified_prompt_stream(
                         )
                         conn.commit()
 
+                # Pflicht für alle Prompt-Typen: Pipeline/Base rufen keinen progress_callback
+                # mit Abschluss auf — ohne dieses Event endet SSE ohne resolve → „Connection to server lost“.
+                try:
+                    sse_payload = json.loads(json.dumps(result, default=str))
+                except (TypeError, ValueError):
+                    sse_payload = {
+                        "type": result.get("type", "unknown"),
+                        "error": "result_not_serializable",
+                    }
+                await event_queue.put({
+                    "type": "execution_complete",
+                    "result": sse_payload,
+                })
+
             except Exception as e:
                 # Queue error event
                 await event_queue.put({

backend/workflow_executor.py

@@ -213,9 +213,11 @@ async def execute_workflow(
 
         logger.info(f"Workflow execution completed: {execution_id}")
 
-        # NEW: Progress-Callback für erfolgreiche Fertigstellung
+        # Fortschritt: kein type=execution_complete — das sendet /execute-stream einmalig
+        # mit vollem execute_prompt_with_data-Result (Pipeline/Base/Workflow), sonst schließt
+        # der Client nach Workflow vorzeitig ohne debug/node_states oder Pipeline bricht ab.
         if progress_callback:
-            await progress_callback("execution_complete", {
+            await progress_callback("workflow_graph_finished", {
                 "execution_id": execution_id,
                 "status": "completed",
                 "aggregated_result": aggregated,

frontend/src/utils/api.js

@@ -512,17 +512,16 @@ export const api = {
             onProgress(data)
           }
 
-          // Check for final result
+          // Check for final result (/execute-stream liefert volles POST-/execute-Payload unter result)
           if (data.type === 'execution_complete') {
-            // Transform SSE result to match regular execute format
-            finalResult = {
+            finalResult = data.result
+              ? data.result
+              : {
                   type: 'workflow',
                   execution_id: data.execution_id,
                   status: data.status,
                   aggregated_result: data.aggregated_result,
-              debug: {
-                node_states: []  // TODO: collect from progress events if needed
-              }
+                  debug: { node_states: [] },
                 }
             eventSource.close()
             resolve(finalResult)