fix(sync-continuation): improve error handling and toast cleanup

- Add proper error handling in executeSyncContinuation with try-catch blocks
- Ensure toast cleanup happens in all error paths via finally block
- Add anchorMessageCount tracking for accurate result fetching after continuation
- Improve fetchSyncResult to filter messages after anchor point
- Add silent failure detection when no new response is generated

src/tools/delegate-task/sync-session-poller.ts

@@ -30,6 +30,7 @@ export async function pollSyncSession(
     agentToUse: string
     toastManager: { removeTask: (id: string) => void } | null | undefined
     taskId: string | undefined
+    anchorMessageCount?: number
   }
 ): Promise<string | null> {
   const syncTiming = getTimingConfig()
@@ -48,7 +49,13 @@ export async function pollSyncSession(
     await new Promise(resolve => setTimeout(resolve, syncTiming.POLL_INTERVAL_MS))
     pollCount++
 
-    const statusResult = await client.session.status()
+    let statusResult: { data?: Record<string, { type: string }> }
+    try {
+      statusResult = await client.session.status()
+    } catch (error) {
+      log("[task] Poll status fetch failed, retrying", { sessionID: input.sessionID, error: String(error) })
+      continue
+    }
     const allStatuses = (statusResult.data ?? {}) as Record<string, { type: string }>
     const sessionStatus = allStatuses[input.sessionID]
 
@@ -65,8 +72,19 @@ export async function pollSyncSession(
       continue
     }
 
-    const messagesResult = await client.session.messages({ path: { id: input.sessionID } })
-    const msgs = ((messagesResult as { data?: unknown }).data ?? messagesResult) as SessionMessage[]
+    let messagesResult: { data?: unknown } | SessionMessage[]
+    try {
+      messagesResult = await client.session.messages({ path: { id: input.sessionID } })
+    } catch (error) {
+      log("[task] Poll messages fetch failed, retrying", { sessionID: input.sessionID, error: String(error) })
+      continue
+    }
+    const rawData = (messagesResult as { data?: unknown })?.data ?? messagesResult
+    const msgs = Array.isArray(rawData) ? (rawData as SessionMessage[]) : []
+
+    if (input.anchorMessageCount !== undefined && msgs.length <= input.anchorMessageCount) {
+      continue
+    }
 
     if (isSessionComplete(msgs)) {
       log("[task] Poll complete - terminal finish detected", { sessionID: input.sessionID, pollCount })