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/tab-posts-render-behavior.test.cjs

@@ -17,7 +17,7 @@ test('missing and invalid tab style use the reference mini layout and ignore glo
   for (const name of ['default', 'invalid']) {
     const current = cases[name];
     assert.equal(current.instance_style, 'mini');
-    assert.match(current.tab_markup, /widget-tab-post style-mini posts-mini-lists zib-widget/);
+    assert.match(current.tab_markup, /widget-tab-post style-mini posts-mini-lists jio-widget-box/);
     assert.match(current.first, /class="posts-mini ajax-item"/);
     assert.doesNotMatch(current.first, /class="mr10"|class="item-meta|class="badg badg-sm/);
     assert.doesNotMatch(current.first, /class="posts-item list|class="posts-item card|class="no_margin/);
@@ -27,7 +27,7 @@ test('missing and invalid tab style use the reference mini layout and ignore glo
 test('un-normalized missing and invalid style use one shared mini resolution in both renderers', () => {
   const cases = render();
   for (const name of ['raw_default', 'raw_invalid']) {
-    assert.match(cases[name].tab_markup, /widget-tab-post style-mini posts-mini-lists zib-widget/);
+    assert.match(cases[name].tab_markup, /widget-tab-post style-mini posts-mini-lists jio-widget-box/);
     assert.match(cases[name].first, /class="posts-mini ajax-item"/);
     assert.doesNotMatch(cases[name].first, /class="posts-item list|class="posts-item card/);
   }
@@ -140,7 +140,7 @@ test('list margin defaults inherit the site setting while an explicit widget fal
 
 test('multi-column frontend output uses the reference widget wrapper and carries layout variables', () => {
   const wrapper = render().frontend_wrapper;
-  assert.match(wrapper, /class="zib-widget-wrap jio-tab-posts-wrap"/);
+  assert.match(wrapper, /class="jio-widget-box-wrap jio-tab-posts-wrap"/);
   assert.match(wrapper, /data-jio-widget="tab_posts" data-widget-id="jio_widget_tab_posts-4"/);
   assert.match(wrapper, /--jio-widget-space-top:8px/);
   assert.match(wrapper, /--jio-widget-space-m-bottom:10px/);