Stop the UI freeze: coalesce snapshot storms and bound chat rendering

Busy agents emitted a snapshot-changed broadcast per tool turn; every event
made the renderer reload the full snapshot while the main process re-read
whole audit tables synchronously, and ChatTimeline re-rendered every message
with per-row linear scans - quadratic work per keystroke of agent activity
until clicks stopped responding. Root fixes at each layer: all broadcasts
funnel through one 200ms-coalesced notifier (unit-tested), the renderer
reloads at most every 800ms with a trailing load, audit/access snapshot
reads use SQL limits instead of full-table scans, and the timeline renders
the latest 150 messages via O(n) lookup maps with a real show-earlier
control. cred.txt is now gitignored so the Composio key cannot leak.

AgentCompany-New/tests/unit/coalesce.test.ts

@@ -0,0 +1,49 @@
+import { afterEach, beforeEach, describe, expect, test, vi } from "vitest";
+import { coalesce } from "../../src/main/app/coalesce";
+
+describe("coalesce", () => {
+  beforeEach(() => {
+    vi.useFakeTimers();
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
+  test("collapses a burst into one trailing call", () => {
+    const calls: number[] = [];
+    const notify = coalesce(() => calls.push(Date.now()), 200);
+    notify();
+    notify();
+    notify();
+    expect(calls).toHaveLength(0);
+    vi.advanceTimersByTime(199);
+    expect(calls).toHaveLength(0);
+    vi.advanceTimersByTime(1);
+    expect(calls).toHaveLength(1);
+  });
+
+  test("fires again for events after the window closes", () => {
+    let count = 0;
+    const notify = coalesce(() => { count += 1; }, 200);
+    notify();
+    vi.advanceTimersByTime(200);
+    expect(count).toBe(1);
+    notify();
+    notify();
+    vi.advanceTimersByTime(200);
+    expect(count).toBe(2);
+  });
+
+  test("an event during the pending window is covered by the trailing call", () => {
+    let count = 0;
+    const notify = coalesce(() => { count += 1; }, 200);
+    notify();
+    vi.advanceTimersByTime(100);
+    notify();
+    vi.advanceTimersByTime(100);
+    expect(count).toBe(1);
+    vi.advanceTimersByTime(200);
+    expect(count).toBe(1);
+  });
+});