feat(blackjack): add split functionality to the game

frontend/src/app/feature/game/blackjack/services/betting.service.ts

@@ -0,0 +1,31 @@
+import { Injectable } from '@angular/core';
+import { FormBuilder, FormGroup, Validators } from '@angular/forms';
+
+@Injectable({
+  providedIn: 'root',
+})
+export class BettingService {
+  constructor(private fb: FormBuilder) {}
+
+  createBetForm(): FormGroup {
+    return this.fb.group({
+      bet: ['', [Validators.required, Validators.min(1)]],
+    });
+  }
+
+  updateBetFormValidators(form: FormGroup, balance: number): void {
+    form.reset();
+    form
+      .get('bet')
+      ?.setValidators([Validators.required, Validators.min(1), Validators.max(balance)]);
+    form.get('bet')?.updateValueAndValidity();
+  }
+
+  calculateBetAmount(balance: number, percentage: number): number {
+    return Math.floor(balance * percentage * 100) / 100;
+  }
+
+  isValidBet(betAmount: number, balance: number): boolean {
+    return betAmount >= 1 && betAmount <= balance;
+  }
+}