chore(branding): remove leftover upstream theme identifiers

The theme was renamed Zibll/子比 → AKSRT → Jio, but upstream branding
survived the sweeps in CSS classes, the SVG sprite prefix, a persisted
widget field ID, JS events, admin Vue class names, test infrastructure
and docblocks.

Renames:
- zib-widget / zib-widget-wrap / zib-slider → jio-widget-box /
  jio-widget-box-wrap / jio-slider-box (jio-widget is taken by the modern
  widget shell, jio-box-* by the card primitives)
- zib-partners-scroll + zps-* → jio-partners-scroll + jps-*
- zib-combo-info-card + zci-* → jio-combo-info-card + jci-*
- zibsvg- → jiosvg-, including the exported picker helpers and the
  fa-zibsvg- family-prefix guard
- zibpay_type → pay_type; the dual-read fallback in PostQuery collapses
  to a single key
- [zibajax="submit"] dropped (no PHP emitter); zib_ajax.success →
  jio_ajax.success
- aks-* admin Vue classes → jio-*
- zib_palette() → palette()

User-facing vendor traces are gone: the floating "more" button default no
longer ships a zibll.com link or 子比主题 marketing copy, the notice
widget ships no preset promo entries, and the four 官网教程 links are
removed from the post-list admin schema.

Test infrastructure renamed to neutral names (docker-compose.reference.yml,
Caddyfile, article-baseline.json, modern-widgets-contract.test.cjs) with
their DB/volume/env/slug identifiers following.

Kept intentionally, documented in tests/fixtures/README.md: the golden
fixture reference fingerprint (a SHA-256 record of an external directory,
read by validate-widget-golden / generate-widget-golden-fixture /
audit-widget-system), the doesNotMatch guards that prove the old tokens are
gone, and the reference theme's own meta key in the visual fixtures.

No backward-compat or data migration: saved widget configs holding old
icon keys or the old field ID silently lose them, per the project's
rewrite-over-compatibility rule.

Verified: 132/132 node contract tests, php tests/widget-system/run.php
(146 assertions), audit-admin-contracts, audit-psr4-paths and
validate-widget-golden all green; tracked bundles regenerated and in sync.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tests/widget-system/auth-source-contract.test.cjs

@@ -28,7 +28,7 @@ test('modal and sign page use one renderer and one state machine', () => {
   assert.doesNotMatch(loader, /sign-register/);
 });
 
-test('static Zibll authentication dimensions and responsive contract are retained', () => {
+test('static authentication dimensions and responsive contract are retained', () => {
   const css = read('assets/css/routes/sign.css');
   assert.match(css, /\.sign\s*\{[\s\S]*?max-width:\s*330px/);
   assert.match(css, /#u_sign\.has-sign-img \.modal-dialog\s*\{\s*width:\s*800px/);
@@ -258,15 +258,15 @@ test('brand icons resolve Gitee and Google to the reference SVG sprite', () => {
 
   // FA5 Free ships no Gitee brand glyph and no multi-colour Google mark, so both
   // resolve to the theme's own symbol sheet exactly like the reference does.
-  assert.match(icons, /'gitee'\s*=>\s*'zibsvg-gitee'/);
-  assert.match(icons, /'google'\s*=>\s*'zibsvg-google-color'/);
+  assert.match(icons, /'gitee'\s*=>\s*'jiosvg-gitee'/);
+  assert.match(icons, /'google'\s*=>\s*'jiosvg-google-color'/);
   assert.match(icons, /'github'\s*=>\s*'fa fab fa-github'/);
   assert.match(icons, /'wechat'\s*=>\s*'fa fab fa-weixin'/);
   assert.match(sprites, /jio_svgs\['gitee'\]/);
   assert.match(sprites, /jio_svgs\['google-color'\]/);
   // Sprite values must reach the shared icon renderer instead of being wrapped
-  // in a bogus <i class="zibsvg-…">.
-  assert.match(icons, /strpos\(\$class, 'zibsvg-'\) === 0[\s\S]*?jio_icon_markup\(\$class, \$extra_classes\)/);
+  // in a bogus <i class="jiosvg-…">.
+  assert.match(icons, /strpos\(\$class, 'jiosvg-'\) === 0[\s\S]*?jio_icon_markup\(\$class, \$extra_classes\)/);
 });
 
 test('the top-nav user popover reproduces the reference quick-login block', () => {