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

apps/server/test/sources-identity/site-center.test.ts

@@ -380,7 +380,7 @@ describe.skipIf(!up)("站点中心(馒头 API 基址)", () => {
       return new Response(JSON.stringify({ code: "0", data: { id: 7, username: "mt", memberCount: {} } }), {
         headers: { "content-type": "application/json" },
       });
-    }) as typeof globalThis.fetch;
+    }) as (input: RequestInfo | URL, init?: RequestInit) => Promise<Response>;
     const h = await createHarness("sitecenter_mtbase", { fetch });
     try {
       const site = await json(