fix(webui): prevent redundant thread and media reloads (#5164)

webui/src/tests/api.test.ts

@@ -103,6 +103,25 @@ describe("webui API helpers", () => {
     );
   });
 
+  it("aborts a WebUI thread request when its caller signal is aborted", async () => {
+    let requestSignal: AbortSignal | null = null;
+    vi.mocked(fetch).mockImplementation((_input, init) => new Promise((_resolve, reject) => {
+      requestSignal = init?.signal ?? null;
+      requestSignal?.addEventListener("abort", () => {
+        reject(new DOMException("Aborted", "AbortError"));
+      });
+    }));
+    const controller = new AbortController();
+
+    const request = fetchWebuiThread("tok", "websocket:chat-1", {
+      signal: controller.signal,
+    });
+    controller.abort();
+
+    await expect(request).rejects.toMatchObject({ name: "AbortError" });
+    expect(requestSignal?.aborted).toBe(true);
+  });
+
   it("percent-encodes websocket keys and paths when fetching file previews", async () => {
     await fetchFilePreview("tok", "websocket:chat-1", "/tmp/project/hook.py:12");