feat: add configurable props for DX improvements

- Configurable keyboard shortcuts (seekSmall, seekLarge, volumeStep, disabled keys)
- Configurable touch gestures (maxSeekSeconds, maxVolumeChange, doubleTapSeekSeconds)
- Configurable auto-hide timeout via controlsAutoHideDelay prop
- Configurable playback rates via playbackRates prop
- Aspect ratio support (16:9, 4:3, 21:9, 1:1, 9:16, custom)
- Extended theme system (fontFamily, borderRadius, overlayOpacity, controlsBackground, etc.)
- Custom translations support via translations prop
- Children/slot system (children, controlsLeftExtra, controlsRightExtra)
- Ref forwarding with VideoPlayerHandle imperative API
- Analytics events (onFirstPlay, onBufferStart, onBufferEnd, onQualityChange)
- iOS Safari volume slider auto-hiding
- SSR guards for feature detection utilities
- prefers-reduced-motion CSS media query support

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/VideoPlayer.css

@@ -7,8 +7,8 @@
   border-radius: var(--player-radius);
   overflow: hidden;
   color: var(--player-text);
-  font-family: 'Inter', 'SF Pro Display', -apple-system, BlinkMacSystemFont, 'Segoe UI',
-    'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
+  font-family: var(--player-font-family, 'Inter', 'SF Pro Display', -apple-system, BlinkMacSystemFont, 'Segoe UI',
+    'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif);
   -webkit-font-smoothing: antialiased;
   -moz-osx-font-smoothing: grayscale;
   user-select: none;
@@ -26,7 +26,7 @@
 .video-player::before {
   content: '';
   display: block;
-  padding-top: 56.25%;
+  padding-top: var(--player-aspect-ratio, 56.25%);
 }
 
 .video-player > * {