fix: harden Pi management readiness

frontend/src/api/client.test.ts

@@ -5,7 +5,7 @@ import { apiFetch } from "./client";
 test("body-less POST omits content-type (avoids Fastify empty-body 400)", async () => {
   let contentType: string | null = "unset";
   server.use(
-    http.post("http://localhost:8787/sessions/s1/resume", ({ request }) => {
+    http.post("/api/sessions/s1/resume", ({ request }) => {
       contentType = request.headers.get("content-type");
       return HttpResponse.json({ id: "s1" });
     }),
@@ -17,7 +17,7 @@ test("body-less POST omits content-type (avoids Fastify empty-body 400)", async
 test("POST with a body sends application/json content-type", async () => {
   let contentType: string | null = null;
   server.use(
-    http.post("http://localhost:8787/sessions/s1/steer", ({ request }) => {
+    http.post("/api/sessions/s1/steer", ({ request }) => {
       contentType = request.headers.get("content-type");
       return new HttpResponse(null, { status: 204 });
     }),