fix(icons): 图标类名统一为 FA5 语法并修正一处失效图标名

主题打包的是 Font Awesome 5，solid 字形必须带样式类 fas。全站有 18 处仍写成
FA4 的裸 fa fa-*，FA5 下并不存在对应字形，表现为图标位置空白；而 FA5-only
契约此前只扫描部分运行时文件，没有覆盖模板与渲染器，这些写法一直没被拦下。

同时发现一处真实的失效图标名：profile-level.php 用的是 fa-line-chart。这是
FA4 名称，FA5 把该系列重命名为 chart-*，正确写法是 fa-chart-line。

- 18 处 "fa fa-*" 补上 fas：首页模板、组件标记、评论表单、用户等级页、菜单
  装饰、SchemaPayment 促销标签默认值、VIP 服务弹窗、ContentRenderer /
  GeneralRenderer、后台卡片样式校验、pay-vip.js
- profile-level.php 的 fa-line-chart 修正为 fa-chart-line
- 三处注释里的示例值同步为合法形态（"fa fas fa-star"），避免被当成正确写法
  抄走；credits.css 注释中直接写出旧字体族名的一处改为描述性表述，否则会被
  FA5-only 契约当作违规命中
- legacy-navigation-contract：FA 资产断言改为跟随 aksrt_enqueue_fontawesome()
  这一间接层（注册点已从脚本文件移到 inc/helpers/aksrt-icons.php），并把
  fa-zibsvg-<key> 识别为项目自有 SVG sprite 族，而非 Font Awesome 字形
- vip-points-exchange-modal 契约同步断言 fa fas fa-angle-right

验证：改动前在干净 HEAD 上跑 node --test（已追踪用例）为 327 项 / 325 通过 /
2 失败，两项失败正是本次修复的失效图标名断言与 FA 版本号断言；改动后 333 项 /
333 通过（含 5 个本地专用用例共 370 项全部通过）。php -l 全部改动的 PHP 文件
通过。

tests/navigation/legacy-navigation-contract.test.cjs

@@ -28,6 +28,13 @@ const scripts = join([
   'src/Core/ScriptsPart1b.php',
   'src/Core/ScriptsPart1c.php',
 ]);
+// The Font Awesome handle is registered inside aksrt_enqueue_fontawesome(), so the
+// 5.15.4 asset contract has to follow that indirection rather than the enqueue call site.
+const iconRuntime = join([
+  'src/Core/ScriptsPart1b.php',
+  'src/Core/ScriptsPart1c.php',
+  'inc/helpers/aksrt-icons.php',
+]);
 const header = join([
   'header.php',
   'inc/helpers/header/aksrt-header-render.php',
@@ -42,7 +49,8 @@ test('the public dependency graph uses WordPress jQuery with the local runtime s
   assert.doesNotMatch(scripts, /wp_deregister_script\('jquery'\)/);
   assert.doesNotMatch(scripts, /jquery\.min\.js'[\s\S]*?'1\.9\.1'/);
   assert.match(scripts, /bootstrap\.min\.css'[\s\S]*?'3\.4\.1'/);
-  assert.match(scripts, /fontawesome5'[\s\S]*?all\.min\.css'[\s\S]*?'5\.15\.4'/);
+  assert.match(scripts, /aksrt_enqueue_fontawesome\(/);
+  assert.match(iconRuntime, /fontawesome5\/css\/all\.min\.css'[\s\S]*?'5\.15\.4'/);
   assert.match(scripts, /main\.min\.css/);
   assert.match(scripts, /loader\.js'[\s\S]*?\['jquery', 'bootstrap'\]/);
   assert.match(read('assets/js/runtime/loader.js'), /tbquire\(\['main'\]\)/);
@@ -107,6 +115,9 @@ test('Font Awesome 5 is the only icon contract across every runtime path', () =>
     'fa-chevron', 'fa-icon', 'fa-icon-picker', 'fa-icons', 'fa-input',
     'fa-mask', 'fa-spin-hover', 'fa-toggle-theme', 'fa-xxx',
   ]);
+  // The theme ships its own SVG sprite family, so fa-zibsvg-<key> is a project
+  // icon rather than a Font Awesome glyph — allow the prefix instead of every key.
+  const projectFamily = /^fa-zibsvg-/;
 
   assert.doesNotMatch(runtime, /\bfa fa-/);
   assert.doesNotMatch(runtime, /FontAwesome|font-awesome\.min\.css|Font Awesome 4|4\.7\.0/);
@@ -114,7 +125,7 @@ test('Font Awesome 5 is the only icon contract across every runtime path', () =>
   assert.doesNotMatch(iconCss, /font:\s*normal\s+normal\s+normal\s+[^;]+Font Awesome 5 Free/);
   assert.equal(exists('assets/css/font-awesome.min.css'), false);
   for (const token of iconTokens) {
-    if (utility.test(token) || custom.has(token)) continue;
+    if (utility.test(token) || custom.has(token) || projectFamily.test(token)) continue;
     assert.ok(fa5.includes(`.${token}:before`), `${token} is not available in Font Awesome 5.15.4`);
   }
 });