feat(sp25): extend TailResource to include acks + ta1_acks

The Acks page needs the same live-tail triplet (useTailStream +
useMergedTail + TailStatusPill) that Claims/Remittances/Activity
already use. The first step is widening the TailResource union so
streamTail("acks") and streamTail("ta1_acks") are valid and the
URL falls out as /api/acks/stream and /api/ta1-acks/stream.

Two new tests assert the URL targets the new backend endpoints.

src/lib/tail-stream.test.ts

@@ -95,6 +95,38 @@ describe("streamTail", () => {
     ]);
   });
 
+  it("test_targets_acks_stream_endpoint", async () => {
+    // SP25: the `acks` resource is part of TailResource; the URL must
+    // be /api/acks/stream so useTailStream("acks") can open it.
+    const driver = makeStream();
+    const fetchMock = vi.fn().mockResolvedValue(driver.response);
+    vi.stubGlobal("fetch", fetchMock);
+    const gen = streamTail("acks");
+    // Drive the generator one step so the fetch() call is reached
+    // before we close the stream.
+    await gen.next();
+    driver.close();
+    await gen.return(undefined);
+    expect(fetchMock).toHaveBeenCalledTimes(1);
+    const [calledUrl] = fetchMock.mock.calls[0] as [string];
+    expect(calledUrl).toBe("/api/acks/stream");
+  });
+
+  it("test_targets_ta1_acks_stream_endpoint", async () => {
+    // SP25: the `ta1_acks` resource is part of TailResource; the URL
+    // must be /api/ta1-acks/stream.
+    const driver = makeStream();
+    const fetchMock = vi.fn().mockResolvedValue(driver.response);
+    vi.stubGlobal("fetch", fetchMock);
+    const gen = streamTail("ta1_acks");
+    await gen.next();
+    driver.close();
+    await gen.return(undefined);
+    expect(fetchMock).toHaveBeenCalledTimes(1);
+    const [calledUrl] = fetchMock.mock.calls[0] as [string];
+    expect(calledUrl).toBe("/api/ta1-acks/stream");
+  });
+
   it("test_handles_heartbeat_silently", async () => {
     // "Silently" here means: still yields the correctly-typed heartbeat
     // (no special filtering) — the consumer (useTailStream) decides what

src/lib/tail-stream.ts

@@ -26,7 +26,7 @@ export type TailEvent =
   | { type: "item_dropped"; data: { id: string } }
   | { type: "error"; data: { message: string } };
 
-export type TailResource = "claims" | "remittances" | "activity";
+export type TailResource = "claims" | "remittances" | "activity" | "acks" | "ta1_acks";
 
 export interface StreamTailOptions {
   /** Forwarded to `fetch`; aborting the controller cleanly exits the generator. */