feat(checkin): open reference-parity details modal from signed buttons

- Rebuild checkin details modal HTML 1:1 with reference theme:
  colorful header c-blue, user card (points/level), daily reward
  card and 7-day continuous mini cards
- Signed entry buttons (header dropdown, user-card badge, user
  center) become clickable checkin-details-link modal triggers
  instead of disabled buttons
- Swap data-signin-btn to details link in place after successful
  signin (reference .initiate-checkin replacement behavior)
- Add aksrt-checkin-details-modal runtime shell (modal-mini 400px)
- Remove dead code: legacy lite modal, admin-ajax details handler,
  /signin/history route, signin calendar; rebuild public bundles
- Update contract tests to the new checkin modal contract

inc/helpers/user-center-renderers/credits-balance.php

@@ -32,9 +32,13 @@ $currency = (string) ($currency_name ?? __('积分', 'aksrt'));
 		</div>
 		<?php if (!empty($signin_enabled)) : ?>
 		<span class="uc-asset-card__head-action muted-color px12" data-aksrt-signin>
+			<?php if (!empty($signin_signed_today)) : ?>
+				<?php echo aksrt_get_user_checkin_details_link('uc-asset-card__signin muted-color px12', '<span>' . esc_html__('已签到', 'aksrt') . '</span><i class="fa fas fa-angle-right em12 ml3" aria-hidden="true"></i>'); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped ?>
+			<?php else : ?>
 			<button type="button" class="uc-asset-card__signin muted-color px12" data-signin-btn data-signin-idle-label="<?php esc_attr_e('签到领积分', 'aksrt'); ?>" data-signin-done-label="<?php esc_attr_e('已签到', 'aksrt'); ?>" disabled>
 				<span data-signin-label><?php esc_html_e('签到领积分', 'aksrt'); ?></span><i class="fa fas fa-angle-right em12 ml3" aria-hidden="true"></i>
 			</button>
+			<?php endif; ?>
 			<span class="uc-asset-card__signin-status" data-signin-status></span>
 		</span>
 		<?php endif; ?>