Add QR code Python MCP server example (#105)

* Add QR code Python MCP server example

A minimal Python MCP server that generates customizable QR codes with an
interactive widget UI. Features:

- Generate QR codes from any text or URL
- Customizable colors, size, border, and error correction
- Interactive widget using MCP Apps SDK protocol
- Supports both HTTP (for web clients) and stdio (for Claude Desktop)

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

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

* Potential fix for code scanning alert no. 10: Client-side cross-site scripting

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

* Add semicolon

* Bind to 0.0.0.0 for Docker compatibility

* Use SDK from unpkg + add CSP resourceDomains for external scripts

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

examples/qr-server/.gitignore

@@ -0,0 +1,25 @@
+# Python virtual environment
+.venv/
+venv/
+env/
+
+# Python cache
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+
+# Distribution / packaging
+dist/
+build/
+*.egg-info/
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db