Reduce agent timeline focus catch-up

packages/app/src/hooks/use-agent-initialization.test.ts

@@ -24,7 +24,7 @@ afterEach(() => {
 });
 
 describe("useAgentInitialization", () => {
-  it("always requests a canonical tail bootstrap even with an authoritative cursor", () => {
+  it("requests bounded canonical catch-up after the current cursor when authoritative history is loaded", () => {
     const client = makeClient();
     useSessionStore.getState().initializeSession(serverId, client as never);
     useSessionStore
@@ -43,6 +43,27 @@ describe("useAgentInitialization", () => {
       void result.current.ensureAgentIsInitialized(agentId);
     });
 
+    expect(client.fetchAgentTimeline).toHaveBeenCalledWith(agentId, {
+      direction: "after",
+      cursor: { epoch: "epoch-1", seq: 42 },
+      limit: TIMELINE_FETCH_PAGE_SIZE,
+      projection: "canonical",
+    });
+    expect(getInitDeferred(getInitKey(serverId, agentId))?.requestDirection).toBe("after");
+  });
+
+  it("requests a bounded canonical tail when no authoritative cursor is available", () => {
+    const client = makeClient();
+    useSessionStore.getState().initializeSession(serverId, client as never);
+
+    const { result } = renderHook(() =>
+      useAgentInitialization({ serverId, client: client as never }),
+    );
+
+    act(() => {
+      void result.current.ensureAgentIsInitialized(agentId);
+    });
+
     expect(client.fetchAgentTimeline).toHaveBeenCalledWith(agentId, {
       direction: "tail",
       limit: TIMELINE_FETCH_PAGE_SIZE,