refactor(core): migrate to Bun and converge acquisition policies and Agent boundaries

packages/agent/test/upstream.test.ts

@@ -150,14 +150,14 @@ describe("按上游装配", () => {
   it("测试补全带 sessionId:OpenCode Go 请求头有 x-opencode-session", async () => {
     const seen: { url: string; headers: Headers }[] = [];
     const orig = globalThis.fetch;
-    globalThis.fetch = (async (input: RequestInfo | URL, init?: RequestInit) => {
-      const req = new Request(input, init);
+    globalThis.fetch = (async (input: string | Request | URL, init?: RequestInit) => {
+      const req = new Request(input instanceof Request ? input : String(input), init);
       seen.push({ url: req.url, headers: req.headers });
       return new Response(JSON.stringify({ error: { message: "stubbed" } }), {
         status: 500,
         headers: { "content-type": "application/json" },
       });
-    }) as typeof fetch;
+    }) as typeof globalThis.fetch;
     try {
       const c = new PiUpstreamClient(
         spec({ provider: "opencode-go", authKind: "api_key" }),