refactor: rename the theme brand and every identifier from AKSRT to Jio

Full-project rename. `git grep -i aksrt` is now empty apart from the
DBMigrator 3.3.0 changelog note that documents the rename itself.

Code identifiers
- PHP namespace AKSRT\ -> Jio\ (composer PSR-4 + 378 declarations)
- global constants AKSRT_* -> JIO_* (VERSION/DIR/URI, PAY_TYPE_*, CAPTCHA_*)
- procedural functions, hooks, options, meta keys, table names,
  cookies, query vars, ajax actions and nonces: aksrt_ -> jio_
- text domain aksrt -> jio; Theme Name -> Jio
- JS globals: aksrtData/aksrtAdminData/... -> jioData/jioAdminData/...,
  window.AKSRTCaptcha & friends -> window.JioCaptcha, Aksrt* -> Jio*
- Vue components Aks*.vue -> Jio*.vue (15 files renamed + imports)
- CSS classes/data-attrs/custom properties: aksrt- -> jio-
- REST namespace aksrt/v1 -> jio/v1 (incl. payment gateway callbacks)

Storage layer
- DB tables {prefix}aksrt_* -> {prefix}jio_*; SCHEMA_VERSION 3.2.0 -> 3.3.0
  so dbDelta creates the new names on install
- widget id_base aksrt_widget_* -> jio_widget_*
- uninstall.php drop list rebuilt from the actual migrator tables
  (dropped 3 stale entries, added the 17 missing ones)

Removed
- hardcoded https://api.aksrt.com/version.json default update endpoint;
  get_endpoint() now reads the 「更新端点」 setting and do_check() no-ops
  when it is empty

Files renamed: inc/helpers/aksrt-*.php -> jio-*.php (54),
assets/admin/src/components/form/Aks*.vue -> Jio*.vue (15).
Build artifacts regenerated: assets/css/build, assets/js/runtime,
assets/admin/build.

Verified: audit-psr4-paths errors=0, audit-admin-contracts errors=0
(warnings=56, unchanged baseline), 813/813 widget-system tests,
44/44 phpunit, php -l clean across all PHP.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

assets/admin/src/components/form/JioSaveBar.vue

@@ -0,0 +1,101 @@
+<template>
+  <div v-if="dirty" class="jio-form-renderer__save-bar">
+    <div class="jio-form-renderer__save-bar__inner">
+      <div class="jio-form-renderer__save-bar__info">
+        <FaIcon icon="fa fas fa-exclamation-circle" :size="14" />
+        <span>您有未保存的更改</span>
+      </div>
+      <div class="jio-form-renderer__save-bar__actions">
+        <n-button size="small" :disabled="saving" @click="emit('reload')">放弃更改</n-button>
+        <n-button
+          size="small"
+          type="primary"
+          :loading="saving"
+          @click="emit('save')"
+        >
+          <FaIcon v-if="!saving" icon="fa fas fa-save" :size="12" />
+          保存设置
+        </n-button>
+      </div>
+    </div>
+  </div>
+</template>
+
+<script setup>
+/**
+ * JioSaveBar — the admin-wide sticky save bar (shown only when dirty).
+ * Shared by JioFormRenderer (schema pages) and custom settings pages.
+ */
+import FaIcon from './FaIcon.vue'
+
+defineProps({
+  dirty: { type: Boolean, default: false },
+  saving: { type: Boolean, default: false },
+})
+
+const emit = defineEmits(['save', 'reload'])
+</script>
+
+<style scoped>
+.jio-form-renderer__save-bar {
+  position: fixed;
+  bottom: 0;
+  left: 0;
+  right: 0;
+  z-index: 1000;
+  background: var(--jio-color-surface);
+  border-top: 1px solid var(--jio-color-border);
+  box-shadow: var(--jio-shadow-floating);
+  animation: slideUp 0.2s ease;
+}
+
+.jio-form-renderer__save-bar__inner {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  max-width: 1100px;
+  margin: 0 auto;
+  padding: 12px 28px;
+  gap: 16px;
+}
+
+.jio-form-renderer__save-bar__info {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  color: #d48806;
+  font-size: 13px;
+}
+
+.jio-form-renderer__save-bar__actions {
+  display: flex;
+  gap: 8px;
+}
+
+@keyframes slideUp {
+  from {
+    transform: translateY(100%);
+    opacity: 0;
+  }
+  to {
+    transform: translateY(0);
+    opacity: 1;
+  }
+}
+
+@media (max-width: 768px) {
+  .jio-form-renderer__save-bar__inner {
+    flex-direction: column;
+    padding: 10px 14px;
+    gap: 8px;
+  }
+
+  .jio-form-renderer__save-bar__actions {
+    width: 100%;
+  }
+
+  .jio-form-renderer__save-bar__actions .n-button {
+    flex: 1;
+  }
+}
+</style>