feat: add Product tags and bulk tag updates

docs/API.md

@@ -96,6 +96,8 @@ POST   /api/v1/admin/inventory/:id/valuation/override
 POST   /api/v1/admin/inventory/:id/pricing/refresh
 POST   /api/v1/admin/bulk
 
+`POST /api/v1/admin/bulk` supports `ARCHIVE`, `PRICING_REFRESH`, and `TAGS` actions. `TAGS` accepts `add` and/or `remove` arrays and applies labels to the selected items' Products.
+
 GET    /api/v1/admin/dashboard
 GET    /api/v1/admin/exports/inventory.json
 GET    /api/v1/admin/exports/inventory.csv

docs/IMPLEMENTATION-STATUS.md

@@ -148,7 +148,7 @@ Remaining roadmap areas are bulk status/tag/pricing actions, richer exports/sett
 - Pricing refresh enqueue now resolves its provider from an active Product mapping and rejects unmapped Products explicitly.
 - Local development and CI can enable a deterministic fixture provider for end-to-end refresh coverage; production provider adapters remain explicitly configured deployment boundaries.
 - Pricing refresh jobs have a bounded three-attempt retry policy with exponential backoff. The worker schedules completed-job cleanup using configurable retention days and cleanup interval settings.
-- Bulk archive and asynchronous bulk pricing refresh are implemented through the seller-scoped API boundary; bulk status changes and tags remain.
+- Bulk archive, asynchronous bulk pricing refresh, and Product-level bulk tag updates are implemented through the seller-scoped API boundary; bulk status changes remain.
 - Admin inventory JSON export is implemented at `GET /api/v1/admin/exports/inventory.json` and serializes seller-scoped admin DTOs as a downloadable attachment.
 - Admin inventory CSV export is implemented at `GET /api/v1/admin/exports/inventory.csv` with escaped spreadsheet-safe fields and seller-scoped admin DTOs.
 - PostgreSQL restore verification and image snapshot restore scripts are implemented and covered by shell tests as part of the deployment drill workflow.