feat(GRO-1173): apply buffer rules UI changes to extracted groombook/web repo

This commit ports the GRO-1173 admin UI changes from the app monorepo
into the extracted groombook/web repo, using the correct source paths
(src/ instead of apps/web/src/):

- New BufferRulesSection component (full CRUD UI for /api/buffer-rules)
- Default Buffer (minutes) field added to service create/edit form
- Size Category and Coat Type dropdowns added to PetForm (portal)
- @groombook/types Service interface extended with defaultBufferMinutes
- BufferRulesSection embedded in Settings page

The PetForm already had coatType — this commit adds petSizeCategory
and renders both fields with proper dropdown selectors.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/types/src/index.ts

@@ -71,6 +71,7 @@ export interface Service {
   basePriceCents: number;
   durationMinutes: number;
   active: boolean;
+  defaultBufferMinutes?: number;
   createdAt: string;
   updatedAt: string;
 }