feat(tags): match add-tag modal to tauri design (preset swatches + active toggle)

- TagsSettingsPage modal: replace native color input with 4 preset
  swatches, add 'وضعیت برچسب' active toggle, update labels and submit
  button to mirror tauri AddPurchaseSubTabModal
- TenantTagController::create now honors an optional 'active' flag
  (defaults true, non-breaking for existing callers)
- tests: backend active-flag case, frontend preset-color + inactive case
- docs/api/tag.md: document the new create 'active' field

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/api/tag.md

@@ -158,12 +158,13 @@ Without `sort`, the default ordering (weight/name) is unchanged.
 
 ### POST `/api/v1/tenant-tag`
 ```json
-{ "name": "فوری", "color": "#FF0000" }
+{ "name": "فوری", "color": "#FF0000", "active": true }
 ```
 | Field | Type | Required | Validation |
 |-------|------|----------|------------|
 | `name` | string | ✅ | غیرخالی، حداکثر ۶۰ |
 | `color` | string | ❌ | هگز `#RRGGBB` یا `#RRGGBBAA` (پیش‌فرض `#5559CE`) |
+| `active` | bool | ❌ | وضعیت اولیه (پیش‌فرض `true`) |
 
 Response `201`: TenantTag object.