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>

assets/js/admin-icon-picker.js

@@ -1,6 +1,6 @@
 /**
  * Jio universal icon picker — shared admin modal for FA5, the built-in
- * SVG sprite and inline custom SVG values ("fa fas fa-star" / "zibsvg-key" /
+ * SVG sprite and inline custom SVG values ("fa fas fa-star" / "jiosvg-key" /
  * "customsvg-<svg>").
  *
  * Any admin screen: call jio_icon_picker_assets() (PHP) and render fields
@@ -62,7 +62,7 @@
     value = String(value || '').trim();
     if (!value) return '';
     if (value.indexOf('customsvg-') === 0) return cleanSvg(value.slice(10));
-    if (value.indexOf('zibsvg-') === 0) {
+    if (value.indexOf('jiosvg-') === 0) {
       const key = value.slice(7).replace(/[^a-zA-Z0-9_-]/g, '');
       return key ? `<svg class="icon" aria-hidden="true"><use xlink:href="#icon-${key}"></use></svg>` : '';
     }
@@ -101,7 +101,7 @@
           // Style-class-only preview: immune to the .fa family override in FA5's css.
           $grid.append(itemButton(value, name, `<i class="${group.id} fa-${escapeText(name)}" aria-hidden="true"></i>`));
         } else if (group.type === 'svg') {
-          const value = `zibsvg-${name}`;
+          const value = `jiosvg-${name}`;
           const key = escapeText(name).replace(/[^a-zA-Z0-9_-]/g, '');
           $grid.append(itemButton(value, name, `<svg class="icon" aria-hidden="true"><use xlink:href="#icon-${key}"></use></svg>`));
         }