feat(blackjack): refresh user balance on game state change

frontend/src/app/service/user.service.ts

@@ -1,7 +1,7 @@
 import { inject, Injectable } from '@angular/core';
 import { HttpClient } from '@angular/common/http';
 import { KeycloakProfile } from 'keycloak-js';
-import { catchError, EMPTY, Observable } from 'rxjs';
+import { BehaviorSubject, catchError, EMPTY, Observable, tap } from 'rxjs';
 import { User } from '../model/User';
 
 @Injectable({
@@ -9,20 +9,39 @@ import { User } from '../model/User';
 })
 export class UserService {
   private http: HttpClient = inject(HttpClient);
+  private currentUserSubject = new BehaviorSubject<User | null>(null);
+  public currentUser$ = this.currentUserSubject.asObservable();
+
+  constructor() {
+    // Initialize with current user data
+    this.getCurrentUser().subscribe();
+  }
 
   public getUser(id: string): Observable<User | null> {
-    return this.http.get<User | null>(`/backend/user/${id}`).pipe(catchError(() => EMPTY));
+    return this.http.get<User | null>(`/backend/user/${id}`).pipe(
+      catchError(() => EMPTY),
+      tap(user => this.currentUserSubject.next(user))
+    );
   }
 
   public getCurrentUser(): Observable<User | null> {
-    return this.http.get<User | null>('/backend/user').pipe(catchError(() => EMPTY));
+    return this.http.get<User | null>('/backend/user').pipe(
+      catchError(() => EMPTY),
+      tap(user => this.currentUserSubject.next(user))
+    );
+  }
+
+  public refreshCurrentUser(): void {
+    this.getCurrentUser().subscribe();
   }
 
   public createUser(id: string, username: string): Observable<User> {
     return this.http.post<User>('/backend/user', {
       keycloakId: id,
       username: username,
-    });
+    }).pipe(
+      tap(user => this.currentUserSubject.next(user))
+    );
   }
 
   public async getOrCreateUser(userProfile: KeycloakProfile) {