feat(antigravity): comprehensive enhancements - model mapping, rate limiting, scheduling & ops

Key changes:
- Upgrade model mapping: Opus 4.5 → Opus 4.6-thinking with precise matching
- Unified rate limiting: scope-level → model-level with Redis snapshot sync
- Load-balanced scheduling by call count with smart retry mechanism
- Force cache billing support
- Model identity injection in prompts with leak prevention
- Thinking mode auto-handling (max_tokens/budget_tokens fix)
- Frontend: whitelist mode toggle, model mapping validation, status indicators
- Gemini session fallback with Redis Trie O(L) matching
- Ops: enhanced concurrency monitoring, account availability, retry logic
- Migration scripts: 049-051 for model mapping unification

frontend/src/api/admin/ops.ts

@@ -337,6 +337,22 @@ export interface OpsConcurrencyStatsResponse {
   timestamp?: string
 }
 
+export interface UserConcurrencyInfo {
+  user_id: number
+  user_email: string
+  username: string
+  current_in_use: number
+  max_capacity: number
+  load_percentage: number
+  waiting_in_queue: number
+}
+
+export interface OpsUserConcurrencyStatsResponse {
+  enabled: boolean
+  user: Record<string, UserConcurrencyInfo>
+  timestamp?: string
+}
+
 export async function getConcurrencyStats(platform?: string, groupId?: number | null): Promise<OpsConcurrencyStatsResponse> {
   const params: Record<string, any> = {}
   if (platform) {
@@ -350,6 +366,11 @@ export async function getConcurrencyStats(platform?: string, groupId?: number |
   return data
 }
 
+export async function getUserConcurrencyStats(): Promise<OpsUserConcurrencyStatsResponse> {
+  const { data } = await apiClient.get<OpsUserConcurrencyStatsResponse>('/admin/ops/user-concurrency')
+  return data
+}
+
 export interface PlatformAvailability {
   platform: string
   total_accounts: number
@@ -1171,6 +1192,7 @@ export const opsAPI = {
   getErrorTrend,
   getErrorDistribution,
   getConcurrencyStats,
+  getUserConcurrencyStats,
   getAccountAvailabilityStats,
   getRealtimeTrafficSummary,
   subscribeQPS,