fix(backoffice): release-candidate walkthrough fixes

- Admin Categories CRUD (create/edit/delete/reorder) silently failed
  end-to-end in local dev: ADMIN_CATEGORIES_GATEWAY resolved
  strategy.getBackofficeProviderMode(), which (unlike
  getBootstrapProviderMode()) has no localhost fallback, so it always
  picked AdminCategoriesApiGateway (real HTTP, 404s here) over the
  purpose-built AdminCategoriesLocalGateway mock. saveDraft()'s
  subscribe() has no error branch, so a create/publish click gave zero
  feedback: the category never saved, dirty stayed true forever, and
  the unsaved-changes guard then blocked navigation with no
  explanation. Live-verified end-to-end: created 3 categories, edited,
  reordered via the keyboard move-up/move-down buttons - all persist
  correctly now. Fixed by wiring the token to the category-specific
  strategy.getCategoryProviderMode() (was already defined, just never
  called) and giving it the same isLocalhost() mock fallback
  getBootstrapProviderMode() already uses. Production behavior
  (non-localhost) is unchanged - still resolves to the real API
  gateway.
- Categories list (tree/table/grid views) mislabeled its Edit button
  'Edit product' (adminProducts.edit) instead of 'Edit category' -
  copy-pasted the wrong existing i18n key; adminCategories.edit
  already exists with the correct translation in en/ru/hy. Not part
  of the tracked ~178-key missing-translation gap (docs/KNOWN-ISSUES.md) -
  this key exists and is simply wrong, not missing.

Verified live via browser walkthrough of every Backoffice route
(dashboard, products list/create/edit, categories list/create/edit/
reorder, orders list/detail, transactions list/detail+audit dialog,
customers list/detail, moderation list+reports queue, users, monitoring,
analytics, media library) at desktop and mobile widths. Console/network
noise from the mock backoffice API 404ing locally is pre-existing and
already documented (docs/ADMIN.md's prior bug-hunt audit pass) - not
re-reported. Product create/edit CRUD already worked end-to-end
(AdminProductsFacade injects its local gateway unconditionally, no
swappable-provider mistake there).

npx tsc --noEmit and npm run build both green (only the pre-existing
700kB initial-bundle budget warning, already tracked as out of scope).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/core/providers/runtime-provider-strategy.service.ts

@@ -48,6 +48,15 @@ export class RuntimeProviderStrategyService {
       return 'mock';
     }
 
+    // Same rationale as getBootstrapProviderMode(): the admin Categories CRUD
+    // gateway has a real local-mock implementation (AdminCategoriesLocalGateway)
+    // built specifically so create/edit/delete/reorder can be exercised without
+    // a backend. Local dev has no reachable backoffice API, so fall back to it
+    // there while production keeps hitting the real API unconditionally.
+    if ((environment as any).useMockBootstrapOnLocal === true && this.isLocalhost()) {
+      return 'mock';
+    }
+
     return 'api';
   }
 }