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/jio-icons.php

@@ -53,11 +53,11 @@ function jio_brand_icon_map(): array {
 	}
 
 	// FA5 Free ships no Gitee brand glyph and no multi-colour Google mark, so
-	// those two resolve to the theme's built-in SVG sprite (zibsvg-*) instead of
+	// those two resolve to the theme's built-in SVG sprite (jiosvg-*) instead of
 	// a solid stand-in; every other key stays on FA5.
 	$map = [
 		'github'    => 'fa fab fa-github',
-		'google'    => 'zibsvg-google-color',
+		'google'    => 'jiosvg-google-color',
 		'x'         => 'fa fab fa-twitter',
 		'twitter'   => 'fa fab fa-twitter',
 		'email'     => 'fa fas fa-envelope',
@@ -75,7 +75,7 @@ function jio_brand_icon_map(): array {
 		'instagram' => 'fa fab fa-instagram',
 		'web'       => 'fa fas fa-globe',
 		'globe'     => 'fa fas fa-globe',
-		'gitee'     => 'zibsvg-gitee',
+		'gitee'     => 'jiosvg-gitee',
 		'baidu'     => 'fa fas fa-paw',
 		'alipay'    => 'fa fab fa-alipay',
 	];
@@ -131,8 +131,8 @@ if (!function_exists('jio_brand_icon_class')) :
 /**
  * Resolve a short key, FA class string or sprite key to its icon value.
  *
- * @param string $name Short key, full FA class string or zibsvg-/customsvg- value.
- * @return string e.g. 'fa fab fa-github' or 'zibsvg-gitee', or '' if unknown.
+ * @param string $name Short key, full FA class string or jiosvg-/customsvg- value.
+ * @return string e.g. 'fa fab fa-github' or 'jiosvg-gitee', or '' if unknown.
  */
 function jio_brand_icon_class(string $name): string {
 	$raw = trim($name);
@@ -142,7 +142,7 @@ function jio_brand_icon_class(string $name): string {
 
 	// Built-in SVG sprite and inline SVG values pass straight through; they are
 	// not FA class strings and must survive to the markup renderer untouched.
-	if (preg_match('/^(?:zibsvg|customsvg)-/i', $raw)) {
+	if (preg_match('/^(?:jiosvg|customsvg)-/i', $raw)) {
 		return $raw;
 	}
 
@@ -174,7 +174,7 @@ if (!function_exists('jio_brand_icon')) :
 /**
  * Escaped markup for a brand/contact icon (FA5 <i> or built-in SVG sprite).
  *
- * @param string       $name          Short key, FA class string or zibsvg-/customsvg- value.
+ * @param string       $name          Short key, FA class string or jiosvg-/customsvg- value.
  * @param array|string $extra_classes Optional extra classes.
  * @return string Safe HTML or empty string when unknown.
  */
@@ -183,7 +183,7 @@ function jio_brand_icon(string $name, $extra_classes = []): string {
 
 	// Sprite and inline-SVG values carry their own element, so the shared icon
 	// renderer owns the markup (it emits <svg class="icon"><use …>).
-	if (strpos($class, 'zibsvg-') === 0 || strpos($class, 'customsvg-') === 0) {
+	if (strpos($class, 'jiosvg-') === 0 || strpos($class, 'customsvg-') === 0) {
 		return jio_icon_markup($class, $extra_classes);
 	}
 
@@ -320,7 +320,7 @@ if (!function_exists('jio_icon_markup')) :
  *  - "fa fas fa-star" / "fa fab fa-weixin" — FA5 class string
  *  - "fa-star"                            — bare glyph, rendered as solid FA5
  *  - legacy FA4 string                    — double-`fa` form, upgraded to FA5
- *  - "zibsvg-hot"                         — theme built-in SVG sprite key
+ *  - "jiosvg-hot"                         — theme built-in SVG sprite key
  *  - "customsvg-<svg …>"                  — inline user SVG markup
  *
  * Output is always FA5 — the legacy FA4 double-`fa` prefix is never emitted.
@@ -357,7 +357,7 @@ function jio_icon_markup(string $value, $extra_classes = []): string {
 		return $svg;
 	}
 
-	if (str_starts_with($value, 'zibsvg-')) {
+	if (str_starts_with($value, 'jiosvg-')) {
 		$key = sanitize_key(substr($value, 7));
 		if ($key === '') {
 			return '';