fix(post): align op permalinks to the outer thread container (#1050)

* fix(post): align op permalinks to the outer thread container

* perf(scroll-to-reply): stop interval when max attempts/duration reached

src/lib/utils/__tests__/misc-utils.test.ts

@@ -1,7 +1,7 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import { copyToClipboard } from '../clipboard-utils';
 import { hashStringToColor, getTextColorForBackground, removeMarkdown } from '../post-utils';
-import { preloadThemeAssets } from '../preload-utils';
+import { preloadReplyModal, preloadThemeAssets } from '../preload-utils';
 import { computeOmittedCount, filterRepliesForDisplay, getPreviewDisplayReplies, getTotalReplyCount } from '../replies-preview-utils';
 import { getQuotedCidsFromContent, mergeQuotedCids } from '../reply-quote-utils';
 import { formatUserIDForDisplay, truncateWithEllipsisInMiddle } from '../string-utils';
@@ -119,6 +119,38 @@ describe('misc utils', () => {
     expect(loadedSources).toEqual(['/buttons/default.png', '/buttons/hover.png', '/backgrounds/wallpaper.png']);
   });
 
+  it('schedules reply modal preload with requestIdleCallback when available', () => {
+    const requestIdleCallback = vi.fn();
+
+    Object.defineProperty(window, 'requestIdleCallback', {
+      configurable: true,
+      value: requestIdleCallback,
+    });
+
+    preloadReplyModal();
+
+    expect(requestIdleCallback).toHaveBeenCalledWith(expect.any(Function), { timeout: 1500 });
+  });
+
+  it('falls back to setTimeout for reply modal preload when requestIdleCallback is unavailable', () => {
+    const originalRequestIdleCallback = window.requestIdleCallback;
+    // @ts-expect-error test fallback path
+    delete window.requestIdleCallback;
+    vi.useFakeTimers();
+    const setTimeoutSpy = vi.spyOn(window, 'setTimeout');
+
+    preloadReplyModal();
+
+    expect(setTimeoutSpy).toHaveBeenCalledWith(expect.any(Function), 500);
+
+    if (originalRequestIdleCallback) {
+      Object.defineProperty(window, 'requestIdleCallback', {
+        configurable: true,
+        value: originalRequestIdleCallback,
+      });
+    }
+  });
+
   it('builds reply previews, omitted counts, and fallback reply totals', () => {
     expect(filterRepliesForDisplay([{ cid: 'visible' }, { cid: 'deleted', deleted: true }, { cid: 'removed', deleted: false }])).toEqual([
       { cid: 'visible' },