Release v0.51.319 — Release KI (Phase 3 light: refresh stale continuation metadata, #3789) (#3795)

Phase-3-LOW. #3789 (@ai-ag2026, refs #3740): refresh stale-indexed compression continuation rows from sidecar; gate excludes session_source='fork' (release-gate MUST-FIX). Full suite 8213, Opus SHIP, Codex MUST-FIX applied, CI 11/11. Co-authored-by: ai-ag2026 <ai-ag2026@users.noreply.github.com>

api/models.py

@@ -2610,11 +2610,27 @@ def _row_may_need_sidecar_metadata_refresh(
     )
     if is_runtime_row:
         return True
+    sid = str(session.get('session_id') or '')
     if not session.get('pre_compression_snapshot'):
-        return False
+        # Refresh a stale-indexed COMPRESSION CONTINUATION row from its sidecar.
+        # Gate tightly: a plain /branch fork also carries parent_session_id
+        # (#1342) but has no compression sidecar drift to correct, and its file
+        # mtime routinely exceeds the indexed logical last_message_at — so
+        # including forks here would call load_metadata_only() on every fork row
+        # on every /api/sessions poll (the molasses #3770 guards against, per the
+        # #3789 release gate). Exclude session_source == 'fork'
+        # (the marker /api/session/branch stamps; see _is_continuation_session)
+        # so only true continuations are eligible.
+        if str(session.get('session_source') or '').strip().lower() == 'fork':
+            return False
+        lineage_shaped = bool(
+            session.get('parent_session_id')
+            or session.get('_lineage_root_id')
+            or session.get('_compression_segment_count')
+        )
+        return bool(lineage_shaped and sid and _sidecar_mtime_after_index_timestamp(session))
     if session.get('message_count') is None or session.get('last_message_at') is None:
         return True
-    sid = str(session.get('session_id') or '')
     return bool(sid and stale_snapshot_ids and sid in stale_snapshot_ids)