feat: add multi-city representation support and domain context resolution

- Created migration to add representation_cities table and domain, is_global fields to representations.
- Implemented SiteContextController to resolve domain to site context (city | representation | unknown).
- Developed DomainContext and DomainContextResolver services for domain mapping.
- Added tests for DomainContextResolver and commission logic based on domain ownership.

assets/admin/types/index.ts

@@ -147,9 +147,12 @@ export interface Representation {
     id: number;
     uuid: string;
     full_name: string;
-    domain?: string;
+    domain?: string | null;
+    is_global?: boolean;
     mobile_number: string | null;
     city_id: number | null;
+    city_ids?: number[];
+    cities?: { id: number; name: string }[];
     city: string | null;
     commission_percent: number;
     bank_account: { card?: string; bank_name?: string; iban?: string } | null;