Uses existing Label/LabelOnItem tables — no schema change. Tags field
in the add/edit dialog: type + Enter/comma to add, backspace to remove,
autocomplete from previously-used labels. Tags display as chips on each
item row. API: POST/PATCH accept tags[], upsert Label rows, sync
LabelOnItem. Catalog endpoint also returns all label names for
autocomplete.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
