Initial commit: modern React video player library

Add all source files for a feature-rich, reusable video player built with React, TypeScript, and Vite. Includes core components, context, hooks, utilities, styles, demo app, and configuration files.

src/components/overlays/LoadingSpinner.tsx

@@ -0,0 +1,13 @@
+import React from 'react'
+import { LoadingIcon } from '../../icons'
+import './LoadingSpinner.css'
+
+export const LoadingSpinner: React.FC = () => {
+  return (
+    <div className="loading-spinner-overlay">
+      <div className="loading-spinner">
+        <LoadingIcon size={48} color="var(--player-primary)" />
+      </div>
+    </div>
+  )
+}