♻️ refactor: simplify streaming message lifecycle management

- Remove unused persistence tracking variables in message handler
- Simplify finalizeResponse logic by removing unnecessary checks
- Change 'finish' event type to 'complete' for consistency
- Add debug logging for streaming events
- Clean up dead code and improve readability

src/main/apiServer/routes/agents/handlers/messages.ts

@@ -49,8 +49,6 @@ export const createMessage = async (req: Request, res: Response): Promise<void>
     // Track stream lifecycle so we keep the SSE connection open until persistence finishes
     let responseEnded = false
     let streamFinished = false
-    let awaitingPersistence = false
-    const persistenceResolved = false
 
     const finalizeResponse = () => {
       if (responseEnded) {
@@ -61,10 +59,6 @@ export const createMessage = async (req: Request, res: Response): Promise<void>
         return
       }
 
-      if (awaitingPersistence && !persistenceResolved) {
-        return
-      }
-
       responseEnded = true
       try {
         res.write('data: {"type":"finish"}\n\n')
@@ -136,7 +130,6 @@ export const createMessage = async (req: Request, res: Response): Promise<void>
             // res.write(`data: ${JSON.stringify({ type: 'complete', result: event.result })}\n\n`)
 
             streamFinished = true
-            awaitingPersistence = true
             finalizeResponse()
             break
           }
@@ -151,7 +144,8 @@ export const createMessage = async (req: Request, res: Response): Promise<void>
 
           default:
             // Handle other event types as generic data
-            res.write(`data: ${JSON.stringify(event)}\n\n`)
+            logger.info(`Streaming message event for session: ${sessionId}:`, { event })
+            // res.write(`data: ${JSON.stringify(event)}\n\n`)
             break
         }
       } catch (writeError) {

src/main/services/agents/services/SessionMessageService.ts

@@ -238,22 +238,15 @@ export class SessionMessageService extends BaseService {
               error: serializeError(underlyingError),
               persistScheduled: false
             })
-            // Always emit a finish chunk at the end
+            // Always emit a complete chunk at the end
             sessionStream.emit('data', {
-              type: 'finish',
+              type: 'complete',
               persistScheduled: false
             })
             break
           }
 
           case 'complete': {
-            const completionPayload = event.result ?? accumulator.toModelMessage('assistant')
-
-            sessionStream.emit('data', {
-              type: 'complete',
-              result: completionPayload
-            })
-
             try {
               const persisted = await this.database.transaction(async (tx) => {
                 const userMessage = await this.persistUserMessage(tx, session.id, req.content, newAgentSessionId)
@@ -278,9 +271,9 @@ export class SessionMessageService extends BaseService {
                 error: serializeError(persistError)
               })
             } finally {
-              // Always emit a finish chunk at the end
+              // Always emit a complete chunk at the end
               sessionStream.emit('data', {
-                type: 'finish',
+                type: 'complete',
                 persistScheduled: true
               })
             }