fix(widgets): preserve badge HTML in icon card title/desc like reference theme

wp_kses_post() strips the custom <badge> element, so icon card title/desc
lost admin-authored markup (e.g. <badge class="ml6 jb-blue">GO</badge>)
both at save time and render time, diverging from the reference theme
which stores and echoes these fields raw.

- add shared inline whitelist (aksrt_icon_card_kses_tags/aksrt_icon_card_kses)
  and route both card renderers plus the media-brand fallback through it
- drop the dead unused $allow array in aksrt_icon_cover_card
- add 'rich_html' sanitize type (FieldSchema + SchemaProvider) and mark
  icon card title/desc fields in widget schemas, page display schema and
  the page config meta box save path
- align header slider card module with reference show_widget_bg branches
  (aksrt-panel/flex1 vs padding-10 wrapper/relative-h)
- update widget contract tests to pin the whitelist behavior

src/Admin/SchemaProvider.php

@@ -821,6 +821,13 @@ class SchemaProvider {
 				return array_values(array_unique($ids));
             case 'html':
                 return wp_kses_post((string) $value);
+            case 'rich_html':
+                // Inline whitelist for card title/desc: `badge` is a custom
+                // element that wp_kses_post() would strip, but legacy (Zibll)
+                // renders such markup verbatim.
+                return function_exists('aksrt_icon_card_kses')
+                    ? aksrt_icon_card_kses((string) $value)
+                    : wp_kses_post((string) $value);
             case 'textarea':
                 return sanitize_textarea_field((string) $value);
             case 'code':