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/discovery-reference-harness.php

@@ -79,7 +79,7 @@ function wp_reset_postdata(): void { $GLOBALS['discovery_current_post'] = null;
 function jio_is_lazy(string $key, bool $default = false): bool { return false; }
 function jio_get_lazy_attr(string $type, string $url, string $class = '', string $lazy = ''): string { return ' class="' . esc_attr($class) . '" src="' . esc_url($url) . '"'; }
 function jio_format_number($number): string { return number_format((int) $number); }
-function jio_renderer_svg_icon(string $name): string { return '<svg class="zibsvg-' . esc_attr($name) . '" viewbox="0 0 16 16" aria-hidden="true"><use href="#zibsvg-' . esc_attr($name) . '"></use></svg>'; }
+function jio_renderer_svg_icon(string $name): string { return '<svg class="jiosvg-' . esc_attr($name) . '" viewbox="0 0 16 16" aria-hidden="true"><use href="#jiosvg-' . esc_attr($name) . '"></use></svg>'; }
 function jio_renderer_collect_post_data(array $config = []): array {
 	$post = $GLOBALS['discovery_current_post'];
 	return ['post_id' => $post->ID, 'title' => '文章 ' . $post->ID, 'subtitle' => '', 'permalink' => 'https://example.test/post/' . $post->ID, 'time_ago' => '2天前', 'views' => 42, 'comments' => 3];