fix: Add file metadata to messages in conversation history

- Updated _add_and_mirror_message to accept file_metadata parameter
- Messages now include file, fileName, fileUrl fields when file is attached
- Fixed issue where file uploaded with message showed has_file: false
- Chat unified now passes file metadata when user sends message with file
- Resolves missing file info in GET /sessions/{id}/history response

api_routes_v2.py

@@ -601,7 +601,7 @@ def _normalize_history_for_api(chat_id: str) -> List[Message]:
     return normalized
 
 
-def _add_and_mirror_message(chat_id: str, role: str, content: str):
+def _add_and_mirror_message(chat_id: str, role: str, content: str, file_metadata: Optional[Dict[str, Any]] = None):
     """
     V3 RULE: Append message to S3 conversation.
     MongoDB metadata updated via _save_conversation_to_s3.
@@ -615,6 +615,15 @@ def _add_and_mirror_message(chat_id: str, role: str, content: str):
         "content": content if isinstance(content, str) else json.dumps(content, ensure_ascii=False),
         "timestamp": datetime.utcnow().isoformat() + "Z"
     }
+    
+    # V3: Include file metadata if provided
+    if file_metadata:
+        new_msg["file"] = True
+        new_msg["fileName"] = file_metadata.get("fileName")
+        new_msg["fileUrl"] = file_metadata.get("fileUrl") or file_metadata.get("s3_uri")
+    else:
+        new_msg["file"] = False
+    
     current_messages.append(new_msg)
     
     # 3. Save to S3 (this updates MongoDB metadata too)
@@ -1039,8 +1048,15 @@ async def chat_unified(
         api_data = {"type": "missing_message"}
         return _assistant_response_payload(chat_id, friendly, {"intent": "missing_message"}, api_data, session.get("state", "initial"))
 
-    # Add user message
-    _add_and_mirror_message(chat_id, "user", message)
+    # Add user message (with file metadata if file was uploaded)
+    file_meta_for_msg = None
+    if file_info:
+        file_meta_for_msg = {
+            "fileName": file.filename if file else None,
+            "fileUrl": file_info.get("s3_uri"),
+            "s3_uri": file_info.get("s3_uri")
+        }
+    _add_and_mirror_message(chat_id, "user", message, file_metadata=file_meta_for_msg)
     # CHANGE: maybe generate a session title after first real user message
     _maybe_generate_chat_name(chat_id)