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>

tests/widget-system/posts-toc-css-contract.test.cjs

@@ -10,7 +10,7 @@ test('article TOC widget uses the shared reference tree styles, not posts-navs p
   const routeCss = read('assets/css/routes/posts-navs.css');
   const mainCss = read('assets/css/main.css');
 
-  assert.doesNotMatch(routeCss, /\.posts-nav-box|\.posts-nav-lists|\.aksrt-section-nav/);
+  assert.doesNotMatch(routeCss, /\.posts-nav-box|\.posts-nav-lists|\.jio-section-nav/);
   for (const selector of [
     '.posts-nav-lists .bl',
     '.posts-nav-lists li.n-H1 a',
@@ -35,6 +35,6 @@ test('mobile TOC panel and its collapse control remain styled and accessible', (
   assert.match(mainCss, /\.posts-nav-lists \.nav-toggle-collapse\s*\{[^}]*border:\s*0;[^}]*background:\s*transparent;/s);
   assert.match(mainCss, /\.posts-nav-box \.posts-nav-lists :where\(a, \.nav-toggle-collapse\):focus-visible/);
   assert.match(mainCss, /@media \(prefers-reduced-motion: reduce\)[\s\S]*?\.posts-nav-lists \.nav-toggle-collapse \{\s*transition:\s*none;/);
-  assert.doesNotMatch(mainCss, /\.mobile-navbar \.posts-nav-box \.aksrt-panel/);
+  assert.doesNotMatch(mainCss, /\.mobile-navbar \.posts-nav-box \.jio-panel/);
   assert.doesNotMatch(read('assets/widgets/frontend.css'), /\.posts-nav-box|\.posts-nav-lists/);
 });