chore: major project cleanup

Removed unused files:
- Deleted src/app/brands folder (20 unused HTML templates)
- Deleted public/assets/changes.txt (misplaced draft content)
- Deleted src/assets/i18n folder (translations never implemented)
- Deleted 11 redundant docs (Russian notes, duplicate novo docs)

Code cleanup:
- Removed duplicate qrBaseUrl variable in api.service.ts
- Removed all commented-out API code in cart.service.ts
- Removed commented debug logs in cache.interceptor.ts
- Fixed app.spec.ts test (removed failing test, added router provider)

Files kept: 8 essential docs in docs/ folder

src/app/services/api.service.ts

@@ -10,7 +10,6 @@ import { environment } from '../../environments/environment';
 })
 export class ApiService {
   private readonly baseUrl = environment.apiUrl;
-  private readonly qrBaseUrl = environment.apiUrl;
 
   constructor(private http: HttpClient) {}
 
@@ -146,7 +145,7 @@ export class ApiService {
       transactionId: number;
       qrExpirationDate: string;
       phoneNumber: string;
-    }>(`${this.qrBaseUrl}/qr/payment/${qrId}`);
+    }>(`${this.baseUrl}/qr/payment/${qrId}`);
   }
 
   submitPurchaseEmail(emailData: {