fix(billing): surface quota saturation events for admin auditing

Thread int32 saturation clamps from tiered settlement and video task
recompute into the consume/task logs under admin_info, so oversized or
malformed billing inputs stay auditable. Clamp negative audio duration
before token conversion and gate the saturation UI markers on admin.

web/default/src/features/usage-logs/components/columns/common-logs-columns.tsx

@@ -104,6 +104,23 @@ function splitQuotaDisplay(value: string): { prefix: string; amount: string } {
 }
 
 function buildDetailSegments(
+  log: UsageLog,
+  other: LogOtherData | null,
+  t: (key: string, opts?: Record<string, unknown>) => string,
+  isAdmin: boolean
+): DetailSegment[] {
+  const segments = buildTypeDetailSegments(log, other, t)
+  // Quota saturation is a rare, admin-only anomaly marker; surface it first
+  // and in danger styling so it stands out on the related billing log. The
+  // backend already strips admin_info for non-admins; gate on isAdmin too as
+  // defense in depth so the marker never leaks if that changes.
+  if (isAdmin && other?.admin_info?.quota_saturation) {
+    return [{ text: t('Quota clamped'), danger: true }, ...segments]
+  }
+  return segments
+}
+
+function buildTypeDetailSegments(
   log: UsageLog,
   other: LogOtherData | null,
   t: (key: string, opts?: Record<string, unknown>) => string
@@ -817,7 +834,7 @@ export function useCommonLogsColumns(isAdmin: boolean): ColumnDef<UsageLog>[] {
         const log = row.original
         const other = parseLogOther(log.other)
 
-        const segments = buildDetailSegments(log, other, t)
+        const segments = buildDetailSegments(log, other, t, isAdmin)
         const primary = segments[0]
         const hasMore = segments.length > 1
 

web/default/src/features/usage-logs/components/dialogs/details-dialog.tsx

@@ -143,6 +143,15 @@ function formatRatio(ratio: number | undefined): string {
   return ratio.toFixed(4)
 }
 
+function quotaSaturationKindLabel(
+  kind: 'overflow' | 'underflow' | 'nan',
+  t: (key: string) => string
+): string {
+  if (kind === 'overflow') return t('Overflow')
+  if (kind === 'underflow') return t('Underflow')
+  return t('Invalid (NaN)')
+}
+
 function BillingBreakdown(props: {
   log: UsageLog
   other: LogOtherData
@@ -704,6 +713,41 @@ export function DetailsDialog(props: DetailsDialogProps) {
           </DetailSection>
         )}
 
+        {/* Quota saturation marker (admin only) */}
+        {props.isAdmin && other?.admin_info?.quota_saturation && (
+          <DetailSection
+            icon={<AlertTriangle className='size-3.5' aria-hidden='true' />}
+            label={t('Quota clamped')}
+            variant='danger'
+          >
+            <p className='mb-1 text-xs wrap-break-word'>
+              {t('Quota saturation protection triggered')}
+            </p>
+            <DetailRow
+              label={t('Kind')}
+              value={quotaSaturationKindLabel(
+                other.admin_info.quota_saturation.kind,
+                t
+              )}
+            />
+            <DetailRow
+              label={t('Original value')}
+              value={String(other.admin_info.quota_saturation.original)}
+              mono
+            />
+            <DetailRow
+              label={t('Clamped to')}
+              value={String(other.admin_info.quota_saturation.clamped)}
+              mono
+            />
+            <DetailRow
+              label={t('Operation')}
+              value={other.admin_info.quota_saturation.op}
+              mono
+            />
+          </DetailSection>
+        )}
+
         {/* Reject reason (admin only) */}
         {props.isAdmin && other?.reject_reason && (
           <DetailSection

web/default/src/features/usage-logs/components/usage-logs-table.tsx

@@ -38,6 +38,7 @@ import {
   LOG_TYPE_ENUM,
 } from '../constants'
 import { useColumnsByCategory } from '../lib/columns'
+import { parseLogOther } from '../lib/format'
 import { fetchLogsByCategory } from '../lib/utils'
 import type { LogCategory } from '../types'
 import { CommonLogsFilterBar } from './common-logs-filter-bar'
@@ -51,6 +52,10 @@ const logTypeRowTint: Record<number, string> = {
   [LOG_TYPE_ENUM.REFUND]: 'bg-blue-50/30 dark:bg-blue-950/15',
 }
 
+// Warning tint for logs where a quota conversion saturated (admin-only marker).
+// Takes precedence over the per-type tint since it flags a billing anomaly.
+const quotaSaturationRowTint = 'bg-amber-50/60 dark:bg-amber-950/25'
+
 function getColumnVisibilityStorageKey(
   logCategory: LogCategory,
   isAdmin: boolean
@@ -204,8 +209,16 @@ export function UsageLogsTable({ logCategory }: UsageLogsTableProps) {
         const logType = (row.original as Record<string, unknown>).type as
           | number
           | undefined
-        const tintClass =
+        let tintClass =
           isCommon && logType != null ? (logTypeRowTint[logType] ?? '') : ''
+        if (isCommon && isAdmin) {
+          const other = parseLogOther(
+            ((row.original as Record<string, unknown>).other as string) ?? ''
+          )
+          if (other?.admin_info?.quota_saturation) {
+            tintClass = quotaSaturationRowTint
+          }
+        }
 
         return (
           <DataTableRow