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/css/routes/links.css

@@ -1,7 +1,7 @@
 /**
- * AKSRT 网址导航 — legacy links page shell/styles.
+ * Jio 网址导航 — legacy links page shell/styles.
  *
- * @package AKSRT
+ * @package Jio
  */
 
 /* ---- cards ---- */
@@ -9,7 +9,7 @@
 	padding: 0 15px 10px;
 }
 
-.links-box:not(.aksrt-panel):not(.links-style-simple):not(.links-style-image) {
+.links-box:not(.jio-panel):not(.links-style-simple):not(.links-style-image) {
 	margin: -5px;
 	display: flex;
 	flex-wrap: wrap;
@@ -33,7 +33,7 @@
 	text-align: center;
 }
 
-.links-box:not(.aksrt-panel) .links-card {
+.links-box:not(.jio-panel) .links-card {
 	background: var(--main-bg-color, var(--surface-1, #fff));
 }
 
@@ -109,8 +109,8 @@
 }
 
 /* ---- fixed category nav ---- */
-.fixed-wrap .fixed-wrap-nav.aksrt-panel,
-.link-nav-box .aksrt-panel {
+.fixed-wrap .fixed-wrap-nav.jio-panel,
+.link-nav-box .jio-panel {
 	padding: 8px 15px;
 }
 
@@ -415,7 +415,7 @@
 		display: block;
 	}
 
-	.link-nav-box > .aksrt-panel {
+	.link-nav-box > .jio-panel {
 		background: transparent;
 		box-shadow: none;
 		padding: 0;