feat(Listings): add map_card_renderer extension point

[nazmulhasan103]

Summary

Two focused additions to eliminate the need for Directorist_Listings instantiation in integrations that only need specific listing output.

1. Helper::get_listing_card_image( int $listing_id ): string

Consolidates the thumb-card template and loop_get_the_thumbnail() into a single static call. No class instantiation, no setup_postdata, no global post state required.

Improvements over the current approach:

• Attachment IDs fetched once, reused for both front image and blur-background layer (previously fetched twice per render)
• Accepts $listing_id directly — no reliance on get_the_ID()
• Private listing_thumbnail_img() handles single image, swiper carousel, and default image fallback

2. Directorist_Listings::$map_card_renderer callable property

Allows integrations to replace the map marker card HTML for both OpenStreet and Google Maps without hooking a global template filter or using shared static state.

Signature: callable( int $listing_id, array $opt ): string

Defaults to null — all existing behaviour fully preserved, zero breaking changes.

$listings->map_card_renderer = function( int $listing_id, array $opt ): string {
    ob_start();
    // render custom markup
    return ob_get_clean();
};
$listings->render_map();
$listings->map_card_renderer = null;

Test plan

• Helper::get_listing_card_image() renders identically to the existing thumb-card template (cover / contain / full modes)
• Blur background mode renders correctly with a single fetch of attachment IDs
• Swiper carousel renders correctly for listings with multiple images
• Default image renders when no images are attached
• map_card_renderer = null (default) — no regression in map rendering
• OpenStreet map: custom renderer output appears in marker popups
• Google Maps: custom renderer output appears in info windows

🤖 Generated with Claude Code

[Armanul46]

Why not use a WordPress filter here instead of a callable property?

$content = apply_filters( 'directorist_map_card_content',
Helper::get_template_contents( 'archive/fields/openstreet-map', $opt ),
$listings_id,
$opt
);
A filter would be the standard WordPress approach — no need to get a reference to the Listings instance, supports multiple callbacks with priority, and works from anywhere (other plugins, themes, functions.php). The callable property limits it to a single renderer and requires direct object access, which isn't how WP plugins typically expose extension points.