Add CLI demo for cli-demo-generator skill

- Created demos/cli-demo-generator/ directory with animated GIF demo
- Generated demo using auto_generate_demo.py showing basic usage
- Updated README.md to include live demo section for cli-demo-generator
- Demo showcases the skill's ability to create animated CLI demos

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

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

demos/cli-demo-generator/generate-demo.tape

@@ -0,0 +1,22 @@
+Output generate-demo.gif
+
+Set FontSize 16
+Set Width 1400
+Set Height 700
+Set Theme "Dracula"
+Set Padding 20
+
+Type "# CLI Demo Generator" Sleep 500ms Enter
+Sleep 1s
+
+Type "# Generate a quick CLI demo" Sleep 500ms
+Enter
+Sleep 2s
+
+Type "scripts/auto_generate_demo.py -c 'echo Hello' -o demo.gif" Sleep 500ms
+Enter
+Sleep 1s
+
+Type "# Demo created successfully\!" Sleep 500ms
+Enter
+Sleep 2s