feat(background-agent): add isUnstableAgent flag for unstable model detection

src/features/background-agent/types.ts

@@ -36,6 +36,8 @@ export interface BackgroundTask {
   concurrencyGroup?: string
   /** Parent session's agent name for notification */
   parentAgent?: string
+  /** Marks if the task was launched from an unstable agent/category */
+  isUnstableAgent?: boolean
 
   /** Last message count for stability detection */
   lastMsgCount?: number
@@ -52,6 +54,7 @@ export interface LaunchInput {
   parentModel?: { providerID: string; modelID: string }
   parentAgent?: string
   model?: { providerID: string; modelID: string; variant?: string }
+  isUnstableAgent?: boolean
   skills?: string[]
   skillContent?: string
 }