sync: bring over remaining release/custom-0.1.115 changes

- Extract PublicSettingsInjectionPayload named struct with drift test
- Add channel_monitor_default_interval_seconds to SSR injection
- Add image_output_price to SupportedModelChip
- Simplify AppSidebar buildSelfNavItems (admins see available channels)
- Add gateway WARN logs for 503 no-available-accounts branches
- Wire ChannelMonitorRunner into provideCleanup for graceful shutdown
- Add migrations 130/131 (CC template userid fix + mimicry field cleanup)
- Clean up fork-only features (sora, claude max simulation, client affinity)
- Remove ~320 obsolete i18n keys
- Add codexUsage utility, WechatServiceButton, BulkEditAccountModal
- Tidy go.sum

frontend/src/components/layout/AppHeader.vue

@@ -125,7 +125,6 @@
                   <Icon name="key" size="sm" />
                   {{ t('nav.apiKeys') }}
                 </router-link>
-
                 <a
                   v-if="authStore.isAdmin"
                   href="https://github.com/Wei-Shaw/sub2api"
@@ -143,7 +142,6 @@
                   </svg>
                   {{ t('nav.github') }}
                 </a>
-
               </div>
 
               <!-- Contact Support (only show if configured) -->

frontend/src/components/layout/AppSidebar.vue

@@ -634,18 +634,15 @@ const ChevronDownIcon = {
 const flagChannelMonitor = makeSidebarFlag(FeatureFlags.channelMonitor)
 const flagPayment = makeSidebarFlag(FeatureFlags.payment)
 const flagAvailableChannels = makeSidebarFlag(FeatureFlags.availableChannels)
-void flagAvailableChannels
 const flagOpsMonitoring = () => adminSettingsStore.opsMonitoringEnabled
 const flagAdminPayment = () => adminSettingsStore.paymentEnabled
 
 // buildSelfNavItems 构造用户自己的导航项（用户端主菜单和管理员的"我的账户"子菜单共享这组声明）。
 // withDashboard=true 时包含仪表盘（用户端），false 时不含（管理员的个人区已经有独立仪表盘入口）。
-// includeAvailableChannels=false 时省略"可用渠道"入口——管理员在 admin 区已经有一个显眼入口，
-// 重复显示会让管理员同时看到两处"可用渠道"。
 //
 // 条目顺序：密钥 → 用量 → 可用渠道 → 渠道状态 → 订阅/支付 → 兑换/资料。
 // 可用渠道紧挨渠道状态之上，让用户"先看自己能用什么、再看对应状态"。
-function buildSelfNavItems(withDashboard: boolean, includeAvailableChannels = true): NavItem[] {
+function buildSelfNavItems(withDashboard: boolean): NavItem[] {
   const items: NavItem[] = []
   if (withDashboard) {
     items.push({ path: '/dashboard', label: t('nav.dashboard'), icon: DashboardIcon })
@@ -653,11 +650,7 @@ function buildSelfNavItems(withDashboard: boolean, includeAvailableChannels = tr
   items.push(
     { path: '/keys', label: t('nav.apiKeys'), icon: KeyIcon },
     { path: '/usage', label: t('nav.usage'), icon: ChartIcon, hideInSimpleMode: true },
-  )
-  if (includeAvailableChannels) {
-    items.push({ path: '/available-channels', label: t('nav.availableChannels'), icon: ChannelIcon, hideInSimpleMode: true, featureFlag: flagAvailableChannels })
-  }
-  items.push(
+    { path: '/available-channels', label: t('nav.availableChannels'), icon: ChannelIcon, hideInSimpleMode: true, featureFlag: flagAvailableChannels },
     { path: '/monitor', label: t('nav.channelStatus'), icon: SignalIcon, featureFlag: flagChannelMonitor },
     { path: '/subscriptions', label: t('nav.mySubscriptions'), icon: CreditCardIcon, hideInSimpleMode: true },
     { path: '/purchase', label: t('nav.buySubscription'), icon: RechargeSubscriptionIcon, hideInSimpleMode: true, featureFlag: flagPayment },
@@ -683,7 +676,9 @@ function finalizeNav(items: NavItem[]): NavItem[] {
 // User navigation items (for regular users)
 const userNavItems = computed((): NavItem[] => finalizeNav(buildSelfNavItems(true)))
 
-// Personal navigation items (for admin's "My Account" section, without Dashboard)
+// Personal navigation items (for admin's "My Account" section, without Dashboard).
+// Admins access 可用渠道 from this section just like regular users — there is no
+// separate admin entry, since the page is purely a user-facing view.
 const personalNavItems = computed((): NavItem[] => finalizeNav(buildSelfNavItems(false)))
 
 // Custom menu items filtered by visibility