feat: finalize pretext feed sizing rollout (#1120)

* feat(feeds): add pretext-backed item sizing across board, catalog, and thread replies

* feat: finalize pretext feed sizing rollout

* fix(catalog): raise multiboard viewport buffer

* fix(board): preserve pretext query overrides

src/hooks/use-reply-height-estimates.ts

@@ -0,0 +1,57 @@
+import { useMemo } from 'react';
+import type { Comment } from '@bitsocialnet/bitsocial-react-hooks';
+import type { SizeFunction } from 'react-virtuoso';
+import { useLocation } from 'react-router-dom';
+import useWindowWidth from './use-window-width';
+import {
+  getReplyHeightEstimates,
+  getReplyItemSizeFromElement,
+  getTypicalReplyHeight,
+  readReplyTypographyMetrics,
+  resolveReplyVirtualizationMode,
+  type ReplyVirtualizationMode,
+} from '../lib/utils/pretext-height-estimates';
+
+interface UseReplyHeightEstimatesOptions {
+  directRepliesByParentCid?: Map<string, Comment[]>;
+  enabled?: boolean;
+  isMobile: boolean;
+  maxContentChars?: number;
+  mode?: ReplyVirtualizationMode;
+  quotedByMap?: Map<string, Comment[]>;
+  replies: Comment[];
+}
+
+const useReplyHeightEstimates = ({ directRepliesByParentCid, enabled = true, isMobile, maxContentChars, mode, quotedByMap, replies }: UseReplyHeightEstimatesOptions) => {
+  const location = useLocation();
+  const windowWidth = useWindowWidth();
+  const themeKey = typeof document !== 'undefined' ? document.body.className : '';
+  const effectiveMode = useMemo(() => mode ?? resolveReplyVirtualizationMode(location.search), [location.search, mode]);
+
+  const metrics = useMemo(() => readReplyTypographyMetrics(), [themeKey, windowWidth]);
+
+  const rawHeightEstimates = useMemo(
+    () =>
+      !enabled
+        ? []
+        : getReplyHeightEstimates({
+            context: 'thread',
+            directRepliesByParentCid,
+            isMobile,
+            maxContentChars,
+            metrics,
+            quotedByMap,
+            replies,
+            windowWidth,
+          }),
+    [directRepliesByParentCid, enabled, isMobile, maxContentChars, metrics, quotedByMap, replies, windowWidth],
+  );
+
+  const heightEstimates = effectiveMode === 'off' ? undefined : rawHeightEstimates;
+  const defaultItemHeight = useMemo(() => getTypicalReplyHeight(rawHeightEstimates, isMobile), [rawHeightEstimates, isMobile]);
+  const itemSize = useMemo<SizeFunction | undefined>(() => (effectiveMode === 'item-size' ? getReplyItemSizeFromElement : undefined), [effectiveMode]);
+
+  return { defaultItemHeight, heightEstimates, itemSize, metrics, mode: effectiveMode, windowWidth };
+};
+
+export default useReplyHeightEstimates;