Reorganize: Move all skills to skills/ folder

- Created skills/ directory
- Moved 272 skills to skills/ subfolder
- Kept agents/ at root level
- Kept installation scripts and docs at root level

Repository structure:
- skills/           - All 272 skills from skills.sh
- agents/           - Agent definitions
- *.sh, *.ps1       - Installation scripts
- README.md, etc.   - Documentation

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

skills/plugins/frontend-design/README.md

@@ -0,0 +1,31 @@
+# Frontend Design Plugin
+
+Generates distinctive, production-grade frontend interfaces that avoid generic AI aesthetics.
+
+## What It Does
+
+Claude automatically uses this skill for frontend work. Creates production-ready code with:
+
+- Bold aesthetic choices
+- Distinctive typography and color palettes
+- High-impact animations and visual details
+- Context-aware implementation
+
+## Usage
+
+```
+"Create a dashboard for a music streaming app"
+"Build a landing page for an AI security startup"
+"Design a settings panel with dark mode"
+```
+
+Claude will choose a clear aesthetic direction and implement production code with meticulous attention to detail.
+
+## Learn More
+
+See the [Frontend Aesthetics Cookbook](https://github.com/anthropics/claude-cookbooks/blob/main/coding/prompting_for_frontend_aesthetics.ipynb) for detailed guidance on prompting for high-quality frontend design.
+
+## Authors
+
+Prithvi Rajasekaran (prithvi@anthropic.com)
+Alexander Bricken (alexander@anthropic.com)