Add WordPress Playground support for the plugin

[valeriu]

Description:

Implement WordPress Playground support for the plugin to enable easier testing and demonstration in an isolated environment.

Scope:

• Add the required Playground configuration files.
• Ensure the plugin can be loaded and activated correctly in Playground.
• Validate that the main plugin functionality works as expected.

Acceptance criteria:

• The plugin can be launched in WordPress Playground.
• The plugin activates without errors.
• The required configuration files are committed to the repository.