fix(kernel): BREAK-02 记忆提取链路闭合 + BREAK-03 审批 HandRun 跟踪

BREAK-02 记忆提取链路闭合:
- Kernel 新增 viking: Arc<VikingAdapter> 共享存储后端
- VikingAdapter 在 boot() 中初始化, 全生命周期共享
- create_middleware_chain() 注册 MemoryMiddleware (priority 150)
- CompactionMiddleware 的 growth 参数从 None 改为 GrowthIntegration
- zclaw-runtime 重新导出 VikingAdapter

BREAK-03 审批后 HandRun 跟踪:
- respond_to_approval() 添加完整 HandRun 生命周期跟踪
- Pending → Running → Completed/Failed 状态转换
- 支持 duration_ms 计时和 cancellation 注册
- 与 execute_hand() 保持一致的跟踪粒度

crates/zclaw-runtime/src/lib.rs

@@ -27,4 +27,5 @@ pub use loop_runner::{AgentLoop, AgentLoopResult, LoopEvent};
 pub use loop_guard::{LoopGuard, LoopGuardConfig, LoopGuardResult};
 pub use stream::{StreamEvent, StreamSender};
 pub use growth::GrowthIntegration;
+pub use zclaw_growth::VikingAdapter;
 pub use compaction::{CompactionConfig, CompactionOutcome};