refactor(core,cli)!: rename SubAgentScope to AgentHeadless

- Rename SubAgentScope → AgentHeadless and runNonInteractive → execute
- Move agents-collab/ into agents/ with new runtime/ subdirectory
- Split subagent.ts into agent-core.ts and agent-headless.ts
- Update all event types, emitters, and statistics classes

BREAKING CHANGE: SubAgentScope renamed to AgentHeadless;
runNonInteractive() renamed to execute()

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

packages/cli/src/ui/AppContainer.test.tsx

@@ -267,7 +267,7 @@ describe('AppContainer State Management', () => {
       listSubagents: vi.fn().mockResolvedValue([]),
       addChangeListener: vi.fn(),
       loadSubagent: vi.fn(),
-      createSubagentScope: vi.fn(),
+      createSubagent: vi.fn(),
     };
     vi.spyOn(mockConfig, 'getSubagentManager').mockReturnValue(
       mockSubagentManager as SubagentManager,