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/post-thumbnail-reference.test.cjs

@@ -15,10 +15,10 @@ test('configured thumbnail ratios override body defaults for both list and card
   assert.match(main, /^body\s*\{[^}]*--posts-card-scale:\s*70%;[^}]*--posts-list-scale:\s*70%;/s);
   for (const [scenario, list, card] of [['defaults', 70, 70], ['custom', 100, 56], ['bounds', 50, 200]]) {
     const html = rendered.styles[scenario];
-    const body = html.match(/<style id="aksrt-theme-color">body\{([^}]+)\}/)[1];
+    const body = html.match(/<style id="jio-theme-color">body\{([^}]+)\}/)[1];
     assert.match(body, new RegExp(`--posts-list-scale:${list}%;`));
     assert.match(body, new RegExp(`--posts-card-scale:${card}%;`));
-    const rootVariables = html.match(/<style id="aksrt-runtime-vars">:root\{([^}]+)\}/)[1];
+    const rootVariables = html.match(/<style id="jio-runtime-vars">:root\{([^}]+)\}/)[1];
     assert.doesNotMatch(rootVariables, /--posts-(list|card)-scale/);
     assert.equal((html.match(/--posts-list-scale:/g) || []).length, 1);
     assert.equal((html.match(/--posts-card-scale:/g) || []).length, 1);