feat: extend comment display to tables/relationships, fix node label redraw

- Parse table-level COMMENT in SQL and Note in DBML; carry through ParsedTable.comment
- Capture [note: '...'] on DBML refs; relationship.comment falls back to FK column comment
- Builder applies labelMode to entity and relationship labels, not just attributes
- Rename zh toggle "属性显示注释" → "显示注释"
- Custom node update() now clears and redraws the group via shared draw helpers, so editing a label updates text and shape size
- After a label edit, refresh the node's connected edges so endpoints re-anchor without needing a manual drag

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: ystemsrx