feat: refine UI design system with polished colors, animations, and components (v4.7.0)

Comprehensive UI overhaul across the Liquid Glass design system:
- Refined color palette with deeper dark mode tones and better contrast
- Updated glass morphism effects with improved blur and saturation values
- Polished Button, Card, Badge, Input, Switch, SegmentedControl components
- Improved VideoCard with poster zoom effect, gradient overlay, and better badge layout
- Refined Navbar with tighter spacing and better icon button hover states
- Enhanced sidebar toggle buttons (rounded-full, better sizing)
- Split PlayerSettings into PlayerSettings + DanmakuSettings (150-line limit)
- Fixed broken rgba(var(--accent-color-rgb)) references with color-mix()
- Added new CSS variables: --radius-xs/sm/md/lg, --shadow-lg, --transition-spring/snappy
- Added staggered children animation and sidebar enter keyframes
- Better scrollbar styling and focus states

Co-Authored-By: Claude Opus 4.6 <[email protected]>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "kvideo",
-  "version": "4.6.0",
+  "version": "4.7.0",
   "private": true,
   "scripts": {
     "dev": "next dev --port ${PORT:-3000}",