Add development tools: .NET SDKs, Cursor IDE, and AI CLI tools

- Install .NET SDK 8.0 and 9.0 with Microsoft package repository
- Add Cursor IDE with AppImage installation and desktop shortcut
- Install Claude CLI from GitHub releases
- Install Gemini CLI via npm
- Update sandbox mode handling for Cursor IDE
- Add API key setup instructions for AI CLI tools

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

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

initial-resource/Desktop/cursor.desktop

@@ -0,0 +1,7 @@
+[Desktop Entry]
+Name=Cursor
+Comment=AI-first code editor
+Exec=/usr/bin/cursor %F
+Icon=cursor
+Terminal=false
+Type=Application