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-render-contract.test.cjs

@@ -20,7 +20,7 @@ test('TOC widget renders one escaped title and asset eligibility follows saved a
   assert.match(fixture.widget, /^<div class="widget-container"><div data-affix="true" class="posts-nav-box"/);
   assert.equal((fixture.widget.match(/data-title=/g) || []).length, 1);
   assert.match(fixture.widget, /&amp;amp; 标题/);
-  assert.doesNotMatch(fixture.widget, /<aside>|class="title-theme"|aksrt-widget-shell/);
+  assert.doesNotMatch(fixture.widget, /<aside>|class="title-theme"|jio-widget-shell/);
 });
 
 test('article TOC renderer owns its reference container and title without the generic title wrapper', () => {
@@ -45,12 +45,12 @@ test('TOC script enqueue follows article visibility settings and per-post overri
   assert.match(scripts, /empty\(\$extension_meta\['no_article-navs'\]\)/);
   assert.match(scripts, /\$requirements\['has_toc'\] = \$is_article && \$article_nav_enabled/);
   assert.doesNotMatch(scripts, /preg_match_all\('\/<h\[1-4\]/);
-  assert.match(scripts, /\$singular_assets\['has_toc'\][\s\S]*?'aksrt-section-navs'/);
+  assert.match(scripts, /\$singular_assets\['has_toc'\][\s\S]*?'jio-section-navs'/);
 
   const pageScripts = read('src/Core/ScriptsPart1b.php');
   const pageBlockStart = pageScripts.indexOf("if (is_page_template('templates/pages/page-posts-navs.php'))");
   const pageBlockEnd = pageScripts.indexOf('// 文章归档页', pageBlockStart);
   const pageBlock = pageScripts.slice(pageBlockStart, pageBlockEnd);
-  assert.match(pageBlock, /aksrt-posts-navs-page/);
-  assert.doesNotMatch(pageBlock, /aksrt-section-navs|section-navs\.js/);
+  assert.match(pageBlock, /jio-posts-navs-page/);
+  assert.doesNotMatch(pageBlock, /jio-section-navs|section-navs\.js/);
 });