feat(agents): Phase 7-10 hook system, plugins, skills, orchestration

Phase 7: Built-in Hooks (audit_log, dangerous_confirmation, security_scan)
Phase 8: Plugin system (PluginManager, PluginSandbox, PluginManifest)
Phase 9: Skills registry (SkillRegistry, local/plugin/MCP loaders)
Phase 10: TeamLeader, RemoteTransport, BackgroundTaskManager

backend/app/agents/orchestration/__init__.py

@@ -0,0 +1,20 @@
+"""高级编排系统 - Phase 10"""
+
+from app.agents.team.leader import TeamLeader, TeamTask, TaskStatus
+from app.agents.transport.remote import RemoteTransport, StructuredMessage
+from app.agents.background.manager import (
+    BackgroundTaskManager,
+    BackgroundTask,
+    get_background_task_manager,
+)
+
+__all__ = [
+    "TeamLeader",
+    "TeamTask",
+    "TaskStatus",
+    "RemoteTransport",
+    "StructuredMessage",
+    "BackgroundTaskManager",
+    "BackgroundTask",
+    "get_background_task_manager",
+]