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/marketplaces/claude-plugins-official/external_plugins/github/.claude-plugin/plugin.json

@@ -0,0 +1,7 @@
+{
+  "name": "github",
+  "description": "Official GitHub MCP server for repository management. Create issues, manage pull requests, review code, search repositories, and interact with GitHub's full API directly from Claude Code.",
+  "author": {
+    "name": "GitHub"
+  }
+}

skills/plugins/marketplaces/claude-plugins-official/external_plugins/github/.mcp.json

@@ -0,0 +1,9 @@
+{
+  "github": {
+    "type": "http",
+    "url": "https://api.githubcopilot.com/mcp/",
+    "headers": {
+      "Authorization": "Bearer ${GITHUB_PERSONAL_ACCESS_TOKEN}"
+    }
+  }
+}