fix: resolve RPC component from hydration boundary

packages/csr/test/reactive.test.ts

@@ -828,6 +828,29 @@ test("component server calls send the CSRF cookie in the RPC header", async () =
   expect(new Headers(request?.headers).get("x-csrf-token")).toBe("rpc token");
 });
 
+test("component server calls use the nearest hydration component identity", async () => {
+  const win = mount(
+    `<div data-scope="" data-wrn-hydration="CButton:abc123">` +
+      `<div data-wrn-events="click"><button data-on-click="server.handleClick()">go</button></div>` +
+      `</div>`,
+  );
+  let payload: { component?: string } | undefined;
+  const globals = globalThis as Record<string, unknown>;
+  const originalFetch = globals.fetch;
+  globals.fetch = async (_input: RequestInfo | URL, init?: RequestInit) => {
+    payload = JSON.parse(String(init?.body));
+    return Response.json({ ok: true });
+  };
+  try {
+    (win.document.querySelector("button") as unknown as HTMLElement).click();
+    await new Promise((resolve) => setTimeout(resolve, 0));
+  } finally {
+    globals.fetch = originalFetch;
+  }
+
+  expect(payload?.component).toBe("CButton");
+});
+
 test("component server calls prefer the rendered CSRF token over stale cookies", async () => {
   const win = mount(
     `<meta name="wrnexus-csrf" content="current-token">` +