feat(memory): sync user entity aliases and metadata to PostgreSQL

- Add `aliases` and `end_user_id` fields to user entity dicts in
  `collect_user_entities_for_metadata` so downstream tasks can write
  them to PostgreSQL
- Add `update_aliases_and_metadata` method to `EndUserInfoRepository`
  for incremental, case-insensitive dedup merge of aliases and
  structured metadata fields
- Add `_sync_end_user_info_pg` helper in tasks.py that writes aliases
  and extracted metadata to `end_user_info`, and back-fills
  `end_user.other_name` when empty
- Call `_sync_end_user_info_pg` from `extract_metadata_batch_task`
  after Neo4j write, and also when no new metadata but aliases exist
- Filter `meta_data` response in `UserMemoryService.get_end_user_info`
  to expose only four core fields: goals, traits, interests, core_facts

api/app/core/memory/storage_services/extraction_engine/knowledge_extraction/metadata_extractor.py

@@ -57,6 +57,8 @@ def collect_user_entities_for_metadata(
                 "entity_id": entity.id,
                 "entity_name": entity.name,
                 "descriptions": descriptions,
+                "aliases": list(entity.aliases or []),
+                "end_user_id": entity.end_user_id,
             })
 
     if user_entities: