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>

inc/helpers/menu-decoration.php

@@ -28,7 +28,7 @@ function jio_menu_pz(int $id, string $key = '', $default = '') {
 }
 
 /**
- * @param string $icon_class Icon-picker value (FA5 class, zibsvg- or customsvg-).
+ * @param string $icon_class Icon-picker value (FA5 class, jiosvg- or customsvg-).
  * @param bool   $enabled    Global switch.
  */
 function jio_render_menu_icon(string $icon_class, bool $enabled = true): string {
@@ -37,8 +37,8 @@ function jio_render_menu_icon(string $icon_class, bool $enabled = true): string
 	}
 
 	// Sprite/inline values must reach jio_icon_markup untouched — the legacy
-	// FA class padding below would corrupt them (zibsvg-hot → fa fas fa-zibsvg-hot).
-	if (str_starts_with($icon_class, 'zibsvg-')) {
+	// FA class padding below would corrupt them (jiosvg-hot → fa fas fa-jiosvg-hot).
+	if (str_starts_with($icon_class, 'jiosvg-')) {
 		return jio_icon_markup($icon_class, 'icon mr3 menu-item-icon');
 	}
 	if (str_starts_with($icon_class, 'customsvg-')) {