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

src/Core/ScriptsPart1c.php

@@ -461,6 +461,8 @@ trait ScriptsPart1c {
             'nonce'                 => wp_create_nonce('aksrt_public_nonce'),
             'restNonce'             => wp_create_nonce('wp_rest'),
             'captchaSignin'         => function_exists('aksrt_is_captcha_enabled_for') && aksrt_is_captcha_enabled_for('signin'),
+            // 已签到详情弹窗（签到成功后就地替换入口按钮用）。
+            'signinDetailsUrl'      => esc_url_raw(rest_url('aksrt/v1/signin/details')),
             'visibilityNonce'       => wp_create_nonce('aksrt_visibility'),
             'siteUrl'               => home_url('/'),
             'themeUrl'              => AKSRT_URI,