Hello World Elementor Widget

Create a production-ready single-file WordPress plugin that adds a custom Elementor widget named "Hello World".

Requirements:

• Must only load if Elementor is active; show an admin notice if Elementor is missing.
• Register the widget via Elementor hooks compatible with Elementor v3+.
• Widget details:
  • Name/slug: p0_hello_world
  • Title: "Hello World"
  • Icon: any appropriate Elementor icon (e.g., eicon-editor-code)
  • Categories: add to a custom category "Plugin0"; if category registration is needed, register it.
  • Keywords: hello, world, plugin0
• Widget controls:
  • Content section:
    • Text control: "Heading" (default "Hello World")
    • Textarea control: "Description" (default "This is a custom Elementor widget.")
  • Style section:
    • Color control for heading color
    • Typography group control for heading
    • Color control for description color
    • Typography group control for description
    • Alignment responsive control applying to wrapper
    • Spacing controls: margin and padding for wrapper
• Frontend output:
  • Render a wrapper div with class p0-hello-world
  • Output heading in an h2 with class p0-hello-world__heading and description in a div with class p0-hello-world__description.
  • Sanitize/escape properly for frontend.
• Editor preview:
  • Implement content_template() for live preview in Elementor editor using Backbone templates.
• Assets:
  • Add minimal CSS, ideally inline via wp_register_style with empty src then wp_add_inline_style, and enqueue only when widget is used if possible; otherwise enqueue on Elementor frontend/editor.
  • CSS should style the wrapper with a subtle border and padding by default.
• Code quality:
  • Use namespaces or class prefixes to avoid collisions.
  • Follow WP coding standards, use hooks init, plugins_loaded, etc.
  • Keep everything in one PHP file.

Also include optional p0_debug logs at key points (e.g., when Elementor missing, when widget registered) without being noisy.