feat(game): add blackjack game component and routing

frontend/src/app/feature/game/blackjack/components/playing-card/playing-card.component.ts

@@ -0,0 +1,30 @@
+import { ChangeDetectionStrategy, Component, Input } from '@angular/core';
+import { CommonModule } from '@angular/common';
+
+@Component({
+  selector: 'app-playing-card',
+  standalone: true,
+  imports: [CommonModule],
+  template: `
+    <div
+      class="w-24 h-36 rounded-lg p-2 relative flex flex-col justify-between shadow-lg"
+      [class]="hidden ? 'bg-red-800' : 'bg-white'"
+    >
+      <span *ngIf="!hidden" class="text-xl font-bold text-accent-red">{{ value }}</span>
+      <span
+        *ngIf="!hidden"
+        class="absolute top-1/2 left-1/2 -translate-x-1/2 -translate-y-1/2 text-3xl text-accent-red"
+        >{{ suit }}</span
+      >
+      <span *ngIf="!hidden" class="text-xl font-bold text-accent-red self-end rotate-180">{{
+        value
+      }}</span>
+    </div>
+  `,
+  changeDetection: ChangeDetectionStrategy.OnPush,
+})
+export class PlayingCardComponent {
+  @Input({ required: true }) value!: string;
+  @Input({ required: true }) suit!: string;
+  @Input({ required: true }) hidden!: boolean;
+}