SD-3357 - fix: dedupe tracked changes from merged activity feed (#3609)

* fix(custom-ui): dedupe tracked changes from merged activity feed (SD-3357)

SuperDoc surfaces tracked changes in both ui.comments.items (as
trackedChange:true comments) and ui.trackChanges.items with the same id.
The ActivitySidebar merged both slices without filtering, so each
suggestion rendered twice (one comment card + one change card). Skip
comment.trackedChange items when building the feed, and drop a leftover
debug log.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(custom-ui): dedupe activity feed by id, not trackedChange flag (SD-3357)

A real comment thread anchored over text that overlaps a suggestion also
gets trackedChange:true (comments.list links it via assignTrackedChangeLink),
so filtering on the flag wrongly hid those discussions. Dedupe by id
instead — synthetic tracked-change comment rows reuse the tracked-change
id, while real comments keep their own. Also exclude pairedWithChangeId so
replacement pairs collapsed by trackChanges.list (replacements: paired)
don't leak one half back as a comment.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix: clarify deduplication logic in activity feed comments

Author: chittolinag

demos/editor/custom-ui/src/components/ActivitySidebar.tsx

@@ -70,9 +70,32 @@ export function ActivitySidebar({ composeOpen, onCloseComposer, decided }: Props
   // (separate ticket), we'll be able to interleave by document
   // position; until then this stable two-bucket ordering matches what
   // the controller used to do internally.
+  //
+  // SuperDoc models tracked changes as comment-linked entities, so
+  // `ui.comments.items` mirrors each tracked change as a synthetic
+  // comment whose id is the tracked-change id. Without de-duping, every
+  // suggestion shows twice (one comment card + one change card).
+  //
+  // We dedupe by id, NOT by the `trackedChange` flag: a real comment
+  // thread also gets `trackedChange: true` when its anchor overlaps a
+  // suggestion (`comments.list()` links it via `assignTrackedChangeLink`),
+  // so a flag filter would wrongly hide those discussions. Only the
+  // synthetic rows reuse a tracked-change id; real comments have their
+  // own. Note: this demo runs `replacements: 'independent'`, so both
+  // sides of a replacement surface as separate change rows and both
+  // synthetic comment ids land in the dedupe set. Under the default
+  // `'paired'` mode the collapsed row drops the delete-side id, which
+  // `trackChanges.list()` does not currently expose — the delete-side
+  // synthetic comment would leak as a duplicate. Engine follow-up needed
+  // before this pattern is safe in paired mode.
   const feed = useMemo<ActivityItem[]>(() => {
+    const changeIds = new Set<string>();
+    for (const tc of trackChanges.items) changeIds.add(tc.id);
     const items: ActivityItem[] = [];
-    for (const c of comments.items) items.push({ kind: 'comment', id: c.id, comment: c });
+    for (const c of comments.items) {
+      if (changeIds.has(c.id)) continue;
+      items.push({ kind: 'comment', id: c.id, comment: c });
+    }
     for (const tc of trackChanges.items) items.push({ kind: 'change', id: tc.id, change: tc.change });
     return items;
   }, [comments.items, trackChanges.items]);