fix: use GET for read-only venue booking abilities

[chubes4]

Problem

ECRoadie_ManageVenueBookings::run_ability() always sends POST to the WordPress Abilities REST run endpoint, including for read-only abilities such as extrachill/list-venue-bookings, extrachill/get-venue-booking, extrachill/get-venue-booking-activity, extrachill/list-booking-holds, and extrachill/list-booking-communications.

WordPress core's WP_REST_Abilities_V1_Run_Controller::validate_request_method() requires GET when an ability declares meta.annotations.readonly = true; POST returns rest_ability_invalid_method with HTTP 405.

Location

• inc/tools/class-manage-venue-bookings.php:226-243
• Core contract: wp-includes/rest-api/endpoints/class-wp-rest-abilities-v1-run-controller.php:101-132

Acceptance criteria

• Dispatch each venue ability with the HTTP method required by its annotations.
• Send read-only ability input through the input query parameter, matching the core run controller contract.
• Keep write abilities on POST with { input: ... } JSON bodies.
• Cover list, inspect, related-read aggregation, and write operations with method/payload assertions.