fix(chat): allow AI to finish and save responses even if client disconnects

src/controllers/chat.controller.ts

@@ -41,10 +41,16 @@ function startSse(res: Response) {
 }
 
 function sseWrite(res: Response, payload: Record<string, unknown>) {
+  if (res.destroyed || res.writableEnded) return;
+  try {
     res.write(`data: ${JSON.stringify(payload)}\n\n`);
     if (typeof (res as any).flush === 'function') {
         (res as any).flush();
     }
+  } catch (err) {
+    // Client disconnect olduysa yazma hatasını yoksay, arka planda AI'ın
+    // yanıt üretmeyi bitirip veritabanına kaydetmesine izin ver.
+  }
 }
 
 interface ChatAttachment { filename: string; text: string; }
@@ -198,10 +204,13 @@ export const chatMessage = async (req: AuthenticatedRequest, res: Response) => {
       }
     }
 
+    if (!res.destroyed && !res.writableEnded) {
       sseWrite(res, { done: true, newTitle, messageId: aiMessage?.id || null });
       res.end();
+    }
   } catch (error: any) {
     console.error('Chat Error:', error);
+    if (!res.destroyed && !res.writableEnded) {
       if (!res.headersSent) {
         res.status(500).json({ error: error.message || 'Internal Server Error' });
       } else {
@@ -209,6 +218,7 @@ export const chatMessage = async (req: AuthenticatedRequest, res: Response) => {
         res.end();
       }
     }
+  }
 };
 
 // Genel (dosyasız) Sohbet/Asistan sayfası için — chat_threads/thread_messages
@@ -281,10 +291,13 @@ export const sendThreadMessage = async (req: AuthenticatedRequest, res: Response
       }
     }
 
+    if (!res.destroyed && !res.writableEnded) {
       sseWrite(res, { done: true, newTitle, messageId: aiMessage?.id || null });
       res.end();
+    }
   } catch (error: any) {
     console.error('Send Thread Message Error:', error);
+    if (!res.destroyed && !res.writableEnded) {
       if (!res.headersSent) {
         res.status(500).json({ error: error.message || 'Internal Server Error' });
       } else {
@@ -292,4 +305,5 @@ export const sendThreadMessage = async (req: AuthenticatedRequest, res: Response
         res.end();
       }
     }
+  }
 };