revert: remove fork-only changes from release sync

Revert payment/wechat, sora/claude-max cleanup, fork-only migrations,
and cosmetic changes that were brought in by the release sync commit.
Keep only channel-monitor related improvements:
- PublicSettingsInjectionPayload named struct with drift test
- ChannelMonitorRunner graceful shutdown in wire
- image_output_price in SupportedModelChip
- Simplified buildSelfNavItems in AppSidebar
- Gateway WARN logs for 503 branches

frontend/src/components/account/BulkEditAccountModal.vue

@@ -698,48 +698,6 @@
         </div>
       </div>
 
-      <!-- Allow Overages (Antigravity only) -->
-      <div v-if="allAntigravity" class="border-t border-gray-200 pt-4 dark:border-dark-600">
-        <div class="flex items-center justify-between">
-          <div class="flex-1 pr-4">
-            <label
-              id="bulk-edit-allow-overages-label"
-              class="input-label mb-0"
-              for="bulk-edit-allow-overages-enabled"
-            >
-              {{ t('admin.accounts.allowOverages') }}
-            </label>
-            <p class="mt-1 text-xs text-gray-500 dark:text-gray-400">
-              {{ t('admin.accounts.allowOveragesTooltip') }}
-            </p>
-          </div>
-          <input
-            v-model="enableAllowOverages"
-            id="bulk-edit-allow-overages-enabled"
-            type="checkbox"
-            aria-controls="bulk-edit-allow-overages-body"
-            class="rounded border-gray-300 text-primary-600 focus:ring-primary-500"
-          />
-        </div>
-        <div v-if="enableAllowOverages" id="bulk-edit-allow-overages-body" class="mt-3">
-          <button
-            type="button"
-            :class="[
-              'relative inline-flex h-6 w-11 flex-shrink-0 cursor-pointer rounded-full border-2 border-transparent transition-colors duration-200 ease-in-out focus:outline-none focus:ring-2 focus:ring-primary-500 focus:ring-offset-2',
-              allowOverages ? 'bg-primary-600' : 'bg-gray-200 dark:bg-dark-600'
-            ]"
-            @click="allowOverages = !allowOverages"
-          >
-            <span
-              :class="[
-                'pointer-events-none inline-block h-5 w-5 transform rounded-full bg-white shadow ring-0 transition duration-200 ease-in-out',
-                allowOverages ? 'translate-x-5' : 'translate-x-0'
-              ]"
-            />
-          </button>
-        </div>
-      </div>
-
       <!-- RPM Limit (仅全部为 Anthropic OAuth/SetupToken 时显示) -->
       <div v-if="allAnthropicOAuthOrSetupToken" class="border-t border-gray-200 pt-4 dark:border-dark-600">
         <div class="mb-3 flex items-center justify-between">
@@ -1009,11 +967,6 @@ const allOpenAIOAuth = computed(() => {
   )
 })
 
-// 是否全部为 Antigravity 平台（allow_overages 仅在此条件下显示）
-const allAntigravity = computed(() =>
-  props.selectedPlatforms.length === 1 && props.selectedPlatforms[0] === 'antigravity'
-)
-
 // 是否全部为 Anthropic OAuth/SetupToken（RPM 配置仅在此条件下显示）
 const allAnthropicOAuthOrSetupToken = computed(() => {
   return (
@@ -1060,7 +1013,6 @@ const enableGroups = ref(false)
 const enableOpenAIPassthrough = ref(false)
 const enableOpenAIWSMode = ref(false)
 const enableRpmLimit = ref(false)
-const enableAllowOverages = ref(false)
 
 // State - field values
 const submitting = ref(false)
@@ -1088,7 +1040,6 @@ const bulkBaseRpm = ref<number | null>(null)
 const bulkRpmStrategy = ref<'tiered' | 'sticky_exempt'>('tiered')
 const bulkRpmStickyBuffer = ref<number | null>(null)
 const userMsgQueueMode = ref<string | null>(null)
-const allowOverages = ref(false)
 const umqModeOptions = computed(() => [
   { value: '', label: t('admin.accounts.quotaControl.rpmLimit.umqModeOff') },
   { value: 'throttle', label: t('admin.accounts.quotaControl.rpmLimit.umqModeThrottle') },
@@ -1330,13 +1281,6 @@ const buildUpdatePayload = (): Record<string, unknown> | null => {
     umqExtra.user_msg_queue_enabled = false  // 清理旧字段（JSONB merge）
   }
 
-  // Allow overages (Antigravity only)
-  if (enableAllowOverages.value) {
-    if (!updates.extra) updates.extra = {}
-    const overagesExtra = updates.extra as Record<string, unknown>
-    overagesExtra.allow_overages = allowOverages.value
-  }
-
   return Object.keys(updates).length > 0 ? updates : null
 }
 
@@ -1401,7 +1345,6 @@ const handleSubmit = async () => {
     enableGroups.value ||
     enableOpenAIWSMode.value ||
     enableRpmLimit.value ||
-    enableAllowOverages.value ||
     userMsgQueueMode.value !== null
 
   if (!hasAnyFieldEnabled) {
@@ -1495,7 +1438,6 @@ watch(
       enableOpenAIPassthrough.value = false
       enableOpenAIWSMode.value = false
       enableRpmLimit.value = false
-      enableAllowOverages.value = false
 
       // Reset all values
       baseUrl.value = ''
@@ -1519,7 +1461,6 @@ watch(
       bulkRpmStrategy.value = 'tiered'
       bulkRpmStickyBuffer.value = null
       userMsgQueueMode.value = null
-      allowOverages.value = false
 
       // Reset mixed channel warning state
       showMixedChannelWarning.value = false