feat(agent): 运行时从 pi-agent-core 0.99.2 迁到 pi-durable 1.1.0 + pi-ai 1.1.0

- PiAgentRuntime 改用 pi-durable Harness:每个 run 一个 JSONL 存储目录 sessionDir/<runId>/ + root 对话;
  系统提示 / 能力工具 / 白名单与预算钩子装在每次运行自己的扩展里;watchEvents 翻译成 AgentRunEvent
- 挂起(工具内 close)立即封口,调用保持未完成,重开后 resume 重放;replayGate 用调用级 memo
- 旧格式 <runId>.jsonl 打开时抛 LegacySessionError;skills 加载与 <skill> 块格式内置(源自 pi-agent-core,MIT)
- tool_call_end 新增可选 durationMs;用量取 pi.usage 合计(整段会话总量)
- Azure provider 改名 azure,迁移 0093 改存量;移除 pi-agent-core,锁 pi-durable/pi-ai/chord 1.1.0
- 文档:ADR-003、pi-providers、runbook、agent README、CHANGELOG

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Cxwgnn2pbzQ7rXv3rq7fei

packages/agent/test/helpers.ts

@@ -106,6 +106,7 @@ export function makeFixture(opts: { slowMs?: number } = {}): Fixture {
 
 export function sleep(ms: number, signal?: AbortSignal): Promise<void> {
   return new Promise((resolve, reject) => {
+    if (signal?.aborted) return reject(new Error("aborted by signal"));
     const t = setTimeout(resolve, ms);
     signal?.addEventListener(
       "abort",