feat(FN-3598): document reply-link threading behavior

Added documentation to the dashboard guide covering reply-link threading behavior (FN-3598 Step 4).

Fusion-Task-Id: FN-3598

scripts/check-test-isolation.mjs

@@ -70,6 +70,7 @@ const RUNTIME_IGNORE_PATTERNS = [
   /^fusion\.db(?:-wal|-shm|-journal)?(?:\.backup-[\w-]+)?$/,
   /^archive\.db(?:-wal|-shm|-journal)?(?:\.backup-[\w-]+)?$/,
   /^activity-log\.jsonl$/,
+  /^settings\.json$/,
   /^logs(?:[\/\\]|$)/,
 ];