polish: Priority 1 improvements - gradients, stats, metadata, footer

✨ Visual Enhancements:
- Unique gradients per tool (green-teal for Vert, orange-pink for Paint, indigo-purple for Pastel)
- Added new gradient utilities for better color differentiation

📊 Stats Section:
- New animated stats component showing "3 Tools, 100% Open Source, ∞ Privacy First"
- Glassmorphism cards with hover effects
- Icon badges for each stat

🔍 Enhanced Metadata:
- Comprehensive Open Graph tags for social sharing
- Twitter Card support
- Enhanced SEO with detailed keywords (vert, paint, pastel)
- Added SVG favicon with gradient toolbox icon
- Viewport meta tag and preconnect optimization

🔗 Improved Footer:
- 3-column responsive layout
- GitHub repository link with icon
- Quick links to all tools (Vert, Paint, Pastel)
- Tool count badge
- Updated tech stack mention (Next.js 16 & Tailwind CSS 4)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/icon.svg

@@ -0,0 +1,18 @@
+<svg width="64" height="64" viewBox="0 0 64 64" fill="none" xmlns="http://www.w3.org/2000/svg">
+  <rect width="64" height="64" rx="12" fill="url(#gradient)"/>
+  <path d="M20 28 L20 42 L34 42 L34 28 Z" stroke="white" stroke-width="3" fill="none" stroke-linecap="round" stroke-linejoin="round"/>
+  <path d="M24 28 Q 27 18, 30 28" stroke="white" stroke-width="3" fill="none" stroke-linecap="round"/>
+  <line x1="22" y1="34" x2="22" y2="39" stroke="white" stroke-width="2.5" stroke-linecap="round"/>
+  <circle cx="22" cy="32" r="1.5" fill="white"/>
+  <line x1="27" y1="34" x2="27" y2="40" stroke="white" stroke-width="2.5" stroke-linecap="round"/>
+  <path d="M24 34 L 27 32 L 30 34" fill="white" stroke="none"/>
+  <rect x="31" y="34" width="2" height="6" fill="white" rx="1"/>
+  <path d="M29 34 L 33 32 L 35 34" fill="white" stroke="none"/>
+  <defs>
+    <linearGradient id="gradient" x1="0" y1="0" x2="64" y2="64">
+      <stop offset="0%" stop-color="#667eea"/>
+      <stop offset="50%" stop-color="#8b5cf6"/>
+      <stop offset="100%" stop-color="#06b6d4"/>
+    </linearGradient>
+  </defs>
+</svg>