Terminal file viewer/editor + per-window app-command lockdown (#60)

Clicking a file path in Claude's terminal output now opens the file in its own window with a CodeMirror 6 editor. The editor highlights the target line, live-reloads while the file changes, and saves explicitly with hash-based conflict detection. The viewer commands are gated by window label.

Every app command is now ACL-gated per window through a Tauri AppManifest. build.rs checks the handler list against the capability files and fails the build on any mismatch.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

app/src/viewer/useViewerPolling.test.ts

@@ -0,0 +1,43 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { renderHook } from "@testing-library/react";
+import { useViewerPolling } from "./useViewerPolling";
+
+describe("useViewerPolling", () => {
+  beforeEach(() => vi.useFakeTimers());
+  afterEach(() => vi.useRealTimers());
+
+  const setVisibility = (state: DocumentVisibilityState) => {
+    Object.defineProperty(document, "visibilityState", { value: state, configurable: true });
+    document.dispatchEvent(new Event("visibilitychange"));
+  };
+
+  it("ticks on the interval only while visible, and once immediately on becoming visible", async () => {
+    setVisibility("visible");
+    const tick = vi.fn(async () => {});
+    renderHook(() => useViewerPolling(2000, tick, true));
+    expect(tick).toHaveBeenCalledTimes(1); // initial
+    await vi.advanceTimersByTimeAsync(4000);
+    expect(tick).toHaveBeenCalledTimes(3);
+    setVisibility("hidden");
+    await vi.advanceTimersByTimeAsync(6000);
+    expect(tick).toHaveBeenCalledTimes(3);
+    setVisibility("visible");
+    expect(tick).toHaveBeenCalledTimes(4);
+  });
+
+  it("does not overlap ticks and stops when disabled", async () => {
+    setVisibility("visible");
+    let resolve: () => void = () => {};
+    const tick = vi.fn(() => new Promise<void>((r) => { resolve = r; }));
+    const { rerender } = renderHook(({ on }) => useViewerPolling(1000, tick, on), { initialProps: { on: true } });
+    await vi.advanceTimersByTimeAsync(3000);
+    expect(tick).toHaveBeenCalledTimes(1);
+    resolve();
+    await vi.advanceTimersByTimeAsync(1000);
+    expect(tick).toHaveBeenCalledTimes(2);
+    rerender({ on: false });
+    resolve();
+    await vi.advanceTimersByTimeAsync(5000);
+    expect(tick).toHaveBeenCalledTimes(2);
+  });
+});