feat(api): maintain assistant content parts and file handling in advanced chat (#24663)

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

api/core/app/apps/advanced_chat/generate_task_pipeline.py

@@ -1,4 +1,5 @@
 import logging
+import re
 import time
 from collections.abc import Callable, Generator, Mapping
 from contextlib import contextmanager
@@ -373,7 +374,7 @@ class AdvancedChatAppGenerateTaskPipeline:
     ) -> Generator[StreamResponse, None, None]:
         """Handle node succeeded events."""
         # Record files if it's an answer node or end node
-        if event.node_type in [NodeType.ANSWER, NodeType.END]:
+        if event.node_type in [NodeType.ANSWER, NodeType.END, NodeType.LLM]:
             self._recorded_files.extend(
                 self._workflow_response_converter.fetch_files_from_node_outputs(event.outputs or {})
             )
@@ -896,7 +897,14 @@ class AdvancedChatAppGenerateTaskPipeline:
 
     def _save_message(self, *, session: Session, graph_runtime_state: Optional[GraphRuntimeState] = None) -> None:
         message = self._get_message(session=session)
-        message.answer = self._task_state.answer
+
+        # If there are assistant files, remove markdown image links from answer
+        answer_text = self._task_state.answer
+        if self._recorded_files:
+            # Remove markdown image links since we're storing files separately
+            answer_text = re.sub(r"!\[.*?\]\(.*?\)", "", answer_text).strip()
+
+        message.answer = answer_text
         message.updated_at = naive_utc_now()
         message.provider_response_latency = time.perf_counter() - self._base_task_pipeline._start_at
         message.message_metadata = self._task_state.metadata.model_dump_json()