refactor: remove Paint tool from toolkit

- Removed Paint card from ToolsGrid
- Updated Stats from 7 to 6 tools
- Updated Footer badge from 7 to 6 tools
- Removed Paint link from Footer tools column
- Removed Paint from README Available Tools section

Current tools (6):
- Vert (file converter)
- Pastel (color toolkit)
- Stirling (PDF toolkit)
- Units (unit converter)
- Draw (whiteboard)
- Figlet (ASCII art)

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

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

components/Footer.tsx

@@ -24,7 +24,7 @@ export default function Footer() {
               Your Creative Toolkit
             </p>
             <div className="mt-4 inline-flex items-center gap-2 px-3 py-1 rounded-full bg-purple-500/10 border border-purple-500/20">
-              <span className="text-xs font-medium text-purple-400">7 Tools</span>
+              <span className="text-xs font-medium text-purple-400">6 Tools</span>
               <span className="text-gray-600">•</span>
               <span className="text-xs text-gray-500">Open Source</span>
             </div>
@@ -61,7 +61,6 @@ export default function Footer() {
             <h4 className="text-sm font-semibold text-gray-300 mb-4">Tools</h4>
             <div className="flex flex-col gap-2 items-center md:items-end">
               <a href="https://vert.kit.pivoine.art" className="text-gray-400 hover:text-[#10b981] transition-colors text-base">Vert</a>
-              <a href="https://paint.kit.pivoine.art" className="text-gray-400 hover:text-[#f97316] transition-colors text-base">Paint</a>
               <a href="https://pastel.kit.pivoine.art" className="text-gray-400 hover:text-[#a855f7] transition-colors text-base">Pastel</a>
               <a href="https://stirling.kit.pivoine.art" className="text-gray-400 hover:text-[#667eea] transition-colors text-base">Stirling</a>
               <a href="https://units.kit.pivoine.art" className="text-gray-400 hover:text-[#2dd4bf] transition-colors text-base">Units</a>