fix(cli): pass action parameter in Purge send_request

[faisalahammad]

Summary

WP-CLI purge commands fail with HTTP 400 because send_request does not include the required action parameter when making requests to admin-ajax.php. This change adds 'action' => 'litespeed_ajax' and uses add_query_arg() to format query parameters into the GET request URL string.

Fixes #963

Changes

cli/purge.cls.php

Before:

	private function send_request( $action, $extra = array() ) {
		$data = array(
			Router::ACTION => $action,
			Router::NONCE => wp_create_nonce( $action ),
		);
		if ( ! empty( $extra ) ) {
			$data = array_merge( $data, $extra );
		}

		$url = admin_url( 'admin-ajax.php' );
		WP_CLI::debug( 'URL is ' . $url );

		$out = WP_CLI\Utils\http_request( 'GET', $url, $data );
		return $out;
	}

After:

	private function send_request( $action, $extra = array() ) {
		$data = array(
			'action'       => 'litespeed_ajax',
			Router::ACTION => $action,
			Router::NONCE  => wp_create_nonce( $action ),
		);
		if ( ! empty( $extra ) ) {
			$data = array_merge( $data, $extra );
		}

		$url = add_query_arg( $data, admin_url( 'admin-ajax.php' ) );
		WP_CLI::debug( 'URL is ' . $url );

		$out = WP_CLI\Utils\http_request( 'GET', $url );
		return $out;
	}

Why: WordPress admin-ajax.php requires an action parameter in $_REQUEST. Passing 'action' => 'litespeed_ajax' and building query arguments with add_query_arg() ensures parameters are properly passed on GET requests.

Testing

Test 1: WP-CLI Purge All

1. Run wp litespeed-purge all
   Result: works as expected, returns success status.

[timotei-litespeed]

@faisalahammad please use branch dev as base
Thank you

[faisalahammad]

Updated base branch to dev and rebased branch onto upstream/dev.