feat(admin): create and batch-generate coupons in dialogs

- Move "新建优惠码" / "批量生成" into header-launched <dialog>s
- Extract forms into PayCouponsForms trait with shared rule fields,
  hints, validation and currency/percent unit switching
- Generated codes card gets a copy-all button; list codes copy on click
- Drop old inline forms, render_generated_dump and the unread
  aksrt_coupon_generated redirect arg

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

assets/js/admin-coupons.js

@@ -0,0 +1,145 @@
+/** 优惠码：新建/批量生成弹窗、类型与范围联动、防重复提交、点击复制。仅本页入队。 */
+(function () {
+  'use strict';
+
+  var root = document.querySelector('.aksrt-coupons-page');
+  if (!root) return;
+  var toast = root.querySelector('[data-aksrt-coupon-toast]');
+  var toastTimer;
+  var forms = Array.from(root.querySelectorAll('[data-aksrt-coupon-form]'));
+
+  function notify(key) {
+    if (!toast) return;
+    clearTimeout(toastTimer);
+    toast.textContent = toast.getAttribute('data-' + key);
+    toast.classList.add('is-visible');
+    toastTimer = setTimeout(function () { toast.classList.remove('is-visible'); }, 3000);
+  }
+
+  /** 类型切换面值的步长/上限与单位；「全部商品」时范围 ID 禁用，否则必填。 */
+  function syncForm(form) {
+    var type = form.elements.type;
+    var value = form.elements.value;
+    var unit = form.querySelector('[data-aksrt-coupon-unit]');
+    if (type && value) {
+      var percent = type.value === 'percent';
+      value.step = percent ? '1' : '0.01';
+      if (percent) value.max = '100'; else value.removeAttribute('max');
+      if (unit) unit.textContent = unit.getAttribute(percent ? 'data-percent' : 'data-fixed');
+    }
+    var scope = form.elements.scope_type;
+    var ids = form.elements.scope_ids;
+    if (scope && ids) {
+      var all = scope.value === '';
+      ids.disabled = all;
+      ids.required = !all;
+    }
+  }
+
+  function lockScroll() {
+    document.documentElement.classList.toggle('aksrt-coupons-modal-open', !!root.querySelector('dialog[open]'));
+  }
+
+  root.querySelectorAll('.aksrt-coupon-dialog').forEach(function (dialog) {
+    if (typeof dialog.showModal !== 'function') return;
+    var opener = null;
+    var startedOutside = false;
+    var form = dialog.querySelector('form');
+
+    function outside(event) {
+      var rect = dialog.getBoundingClientRect();
+      return event.clientX < rect.left || event.clientX > rect.right || event.clientY < rect.top || event.clientY > rect.bottom;
+    }
+    function requestClose() {
+      if (!form.dataset.submitting) dialog.close();
+    }
+
+    root.querySelectorAll('[data-aksrt-dialog-open="' + dialog.id + '"]').forEach(function (button) {
+      button.addEventListener('click', function () {
+        opener = button;
+        syncForm(form);
+        dialog.showModal();
+        lockScroll();
+      });
+    });
+    dialog.querySelectorAll('[data-aksrt-dialog-close]').forEach(function (button) {
+      button.addEventListener('click', requestClose);
+    });
+    dialog.addEventListener('pointerdown', function (event) {
+      startedOutside = event.target === dialog && outside(event);
+    });
+    dialog.addEventListener('click', function (event) {
+      if (startedOutside && event.target === dialog && outside(event)) requestClose();
+      startedOutside = false;
+    });
+    dialog.addEventListener('cancel', function (event) {
+      if (form.dataset.submitting) event.preventDefault();
+    });
+    dialog.addEventListener('close', function () {
+      lockScroll();
+      if (opener && opener.isConnected) opener.focus();
+      opener = null;
+    });
+  });
+
+  forms.forEach(function (form) {
+    var submit = form.querySelector('[data-aksrt-coupon-submit]');
+    if (submit) submit.setAttribute('data-idle-label', submit.textContent);
+    form.addEventListener('change', function () { syncForm(form); });
+    form.addEventListener('submit', function (event) {
+      if (form.dataset.submitting) {
+        event.preventDefault();
+        return;
+      }
+      form.dataset.submitting = '1';
+      if (submit) {
+        submit.textContent = form.getAttribute('data-busy-label');
+        // 延后禁用：同步禁用 submit 按钮会让部分浏览器丢掉这次提交。
+        setTimeout(function () { submit.disabled = true; }, 0);
+      }
+    });
+    syncForm(form);
+  });
+
+  root.addEventListener('click', async function (event) {
+    var button = event.target.closest('[data-clipboard-text]');
+    if (!button) return;
+    var value = button.getAttribute('data-clipboard-text');
+    try {
+      if (navigator.clipboard && window.isSecureContext) {
+        await navigator.clipboard.writeText(value);
+      } else {
+        var input = document.createElement('textarea');
+        input.value = value;
+        input.className = 'screen-reader-text';
+        root.appendChild(input);
+        input.select();
+        var copied = false;
+        try {
+          copied = document.execCommand('copy');
+        } finally {
+          input.remove();
+          button.focus();
+        }
+        if (!copied) throw new Error('copy');
+      }
+      notify('copied');
+    } catch (error) {
+      notify('copy-failed');
+    }
+  });
+
+  // bfcache 返回时恢复按钮，避免表单停在提交中状态。
+  window.addEventListener('pageshow', function () {
+    forms.forEach(function (form) {
+      var submit = form.querySelector('[data-aksrt-coupon-submit]');
+      delete form.dataset.submitting;
+      if (submit) {
+        submit.disabled = false;
+        submit.textContent = submit.getAttribute('data-idle-label');
+      }
+      syncForm(form);
+    });
+    lockScroll();
+  });
+})();