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/tab-posts-style-contract.test.cjs

@@ -30,7 +30,7 @@ test('tab and single post widget titles restore reference weight while preservin
   assert.equal(declarations('.widget-tab-post .item-heading.font-bold')['font-weight'], '700');
   assert.equal(declarations('.widget-main-post .item-heading')['font-weight'], '500');
   assert.equal(declarations('.widget-main-post .item-heading.font-bold')['font-weight'], '700');
-  const shell = declarations('.aksrt-tab-posts-wrap');
+  const shell = declarations('.jio-tab-posts-wrap');
   assert.equal(shell['font-size'], '14px');
   assert.equal(shell['line-height'], '1.42857143');
   assert.equal(shell.color, 'var(--main-color,#4e5358)');
@@ -40,7 +40,7 @@ test('tab and single post widget titles restore reference weight while preservin
   assert.equal(declarations('.widget-main-post .posts-mini-con').flex, 'auto');
   assert.equal(declarations('.widget-tab-post .item-meta .meta-pay').cursor, 'auto');
   assert.equal(declarations('.widget-main-post .item-meta .meta-pay').cursor, 'auto');
-  assert.match(css, /\.aksrt-posts-wrap :where\(a, button, input, select, textarea, \[tabindex\]\):focus-visible/);
+  assert.match(css, /\.jio-posts-wrap :where\(a, button, input, select, textarea, \[tabindex\]\):focus-visible/);
 });
 
 test('widget pagination restores compact reference metrics over public pagination overrides', () => {
@@ -88,7 +88,7 @@ test('modern tabs have one interaction owner and no retired tab selector or unus
   const runtime = read('assets/widgets/frontend.js');
   const renderer = read('src/WidgetSystem/PostRenderer.php');
   assert.doesNotMatch(content, /data-toggle="tab"|data-ajax/);
-  assert.doesNotMatch(runtime, /aksrt-widget-tabs/);
+  assert.doesNotMatch(runtime, /jio-widget-tabs/);
   assert.doesNotMatch(renderer, /widget_style/);
   assert.match(runtime, /scope\.querySelectorAll\('\.widget-tab-post'\)\.forEach\(initTabs\)/);
 });