fix(frontend): align the user-card check-in badge with the reference theme

The legacy .jb-* compat layer in core/buttons.css restated .jb-yellow as #f99d4d -> #f7631d, and because the public bundle loads after main.min.css that value overrode the reference-accurate #f59f54 -> #ff6922 gradient, so the check-in bookmark (and every other .jb-yellow surface) painted the wrong orange. Correct the gradient and rebuild the public bundle.

Also drop the dead is-done class and the attribute-less span wrapper from the signed card badge, which the reference theme does not have. The header dropdown variant keeps its class, locked by the navigation contract.

inc/helpers/aksrt-header-userbox.php

@@ -56,11 +56,11 @@ if (!function_exists('aksrt_header_user_checkin_btn')) :
 		// 已签到：与参考主题一致，入口按钮变为签到详情弹窗触发链接（可点击）。
 		if ($signed) {
 			if ($class !== null) {
-				// 用户卡片签到书签：保留书签类与 is-done 视觉，仅将行为切换为打开详情弹窗。
+				// 用户卡片签到书签：与参考主题一致，已签到态仅切换为详情弹窗触发链接，书签类名与文本不变。
 				return aksrt_get_user_checkin_details_link(
-					$class . ' is-done',
+					$class,
 					'<i class="fa far fa-calendar-check ml3 mr6" aria-hidden="true"></i>'
-					. '<span>' . esc_html__('已签到', 'aksrt') . '</span>'
+					. esc_html__('已签到', 'aksrt')
 				);
 			}
 			return aksrt_get_user_checkin_details_link(