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/posts-renderer/post-data.php

@@ -225,7 +225,7 @@ if (!function_exists('jio_renderer_compact_pay_badge')) {
 				$label = esc_html__('会员专属', 'jio');
 			} else {
 				$display = \Jio\Settings\Settings::get_paid_content_settings()['display'];
-				$mark = $points ? jio_icon_markup('zibsvg-points', 'points-mark') : esc_html((string) ($display['currency_symbol'] ?? '￥'));
+				$mark = $points ? jio_icon_markup('jiosvg-points', 'points-mark') : esc_html((string) ($display['currency_symbol'] ?? '￥'));
 				$label = '<span class="em09">' . $mark . '</span>' . esc_html($price);
 			}
 		}
@@ -280,7 +280,7 @@ if (!function_exists('jio_renderer_meta_number')) {
 
 if (!function_exists('jio_renderer_svg_icon')) {
 	function jio_renderer_svg_icon(string $name): string {
-		return jio_icon_markup('zibsvg-' . $name);
+		return jio_icon_markup('jiosvg-' . $name);
 	}
 }