chore: import upstream snapshot with attribution

examples/v2/angular/storybook/components/custom-scroll-button.component.ts

@@ -0,0 +1,62 @@
+import { Component, Input, Output, EventEmitter } from "@angular/core";
+import { CommonModule } from "@angular/common";
+
+@Component({
+  selector: "custom-scroll-button",
+  standalone: true,
+  imports: [CommonModule],
+  template: `
+    <button
+      type="button"
+      (click)="handleClick()"
+      [class]="inputClass"
+      [class.hover]="isHovered"
+      (mouseenter)="isHovered = true"
+      (mouseleave)="isHovered = false"
+      style="
+        position: fixed;
+        bottom: 100px;
+        right: 20px;
+        width: 60px;
+        height: 60px;
+        border-radius: 50%;
+        background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
+        border: 3px solid white;
+        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
+        cursor: pointer;
+        pointer-events: auto;
+        display: flex;
+        align-items: center;
+        justify-content: center;
+        transition: transform 0.2s;
+        z-index: 1000;
+      "
+      [style.transform]="isHovered ? 'scale(1.1)' : 'scale(1)'"
+    >
+      <span style="color: white; font-size: 24px; pointer-events: none">⬇️</span>
+    </button>
+  `,
+  styles: [
+    `
+      button.hover {
+        transform: scale(1.1);
+      }
+    `,
+  ],
+})
+export class CustomScrollButtonComponent {
+  @Input() onClick?: () => void;
+  @Input() inputClass?: string;
+  @Output() clicked = new EventEmitter<void>();
+
+  isHovered = false;
+
+  handleClick() {
+    // Emit the clicked event for the slot system to handle
+    this.clicked.emit();
+    // Also call onClick if provided for backward compatibility
+    if (this.onClick) {
+      this.onClick();
+    }
+  }
+}