feat: Import 35+ skills, merge duplicates, add openclaw installer

Major updates:
- Added 35+ new skills from awesome-opencode-skills and antigravity repos
- Merged SEO skills into seo-master
- Merged architecture skills into architecture
- Merged security skills into security-auditor and security-coder
- Merged testing skills into testing-master and testing-patterns
- Merged pentesting skills into pentesting
- Renamed website-creator to thai-frontend-dev
- Replaced skill-creator with github version
- Removed Chutes references (use MiniMax API instead)
- Added install-openclaw-skills.sh for cross-platform installation
- Updated .env.example with MiniMax API credentials

skills/theme-factory/themes/modern-minimalist.md

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+# Modern Minimalist
+
+A clean and contemporary theme with a sophisticated grayscale palette for maximum versatility.
+
+## Color Palette
+
+- **Charcoal**: `#36454f` - Primary dark color
+- **Slate Gray**: `#708090` - Medium gray for accents
+- **Light Gray**: `#d3d3d3` - Backgrounds and dividers
+- **White**: `#ffffff` - Text and clean backgrounds
+
+## Typography
+
+- **Headers**: DejaVu Sans Bold
+- **Body Text**: DejaVu Sans
+
+## Best Used For
+
+Tech presentations, architecture portfolios, design showcases, modern business proposals, data visualization.