feat(ops): add usage_logs partition status to ops dashboard

Add partition management integration to the smart ops system:
- Backend: Add GetUsageLogsPartitionStatus endpoint in OpsHandler
- Backend: Add partition query methods in OpsRepository
- Backend: Add UsageLogsPartitionStatus type in OpsService
- Frontend: Add OpsPartitionStatusCard component
- Frontend: Add partition status display in OpsDashboard
- i18n: Add Chinese and English translations

The partition status card shows:
- Whether usage_logs is partitioned
- Current row count vs threshold (100K)
- Partition count (if partitioned)
- Warning message when partitioning is recommended

This allows administrators to monitor partition status directly
from the ops dashboard without checking server logs.

frontend/src/api/admin/ops.ts

@@ -950,6 +950,23 @@ export interface OpsSystemLogSinkHealth {
   last_error?: string
 }
 
+// ==================== Usage Logs Partition Management ====================
+
+export interface UsageLogsPartitionStatus {
+  is_partitioned: boolean
+  row_count: number
+  partition_count: number
+  threshold_rows: number
+  needs_partitioning: boolean
+  warning_level: 'none' | 'info' | 'warning'
+  last_checked_at: string
+}
+
+export async function getUsageLogsPartitionStatus(): Promise<UsageLogsPartitionStatus> {
+  const { data } = await apiClient.get<UsageLogsPartitionStatus>('/admin/ops/partition-status')
+  return data
+}
+
 export interface OpsErrorLog {
   id: number
   created_at: string
@@ -1450,7 +1467,10 @@ export const opsAPI = {
   updateMetricThresholds,
   listSystemLogs,
   cleanupSystemLogs,
-  getSystemLogSinkHealth
+  getSystemLogSinkHealth,
+
+  // Usage logs partition management
+  getUsageLogsPartitionStatus
 }
 
 export default opsAPI