feat: add quota limit for API key accounts

- Add configurable spending limit (quota_limit) for apikey-type accounts
- Atomic quota accumulation via PostgreSQL JSONB operations on TotalCost
- Scheduler filters out over-quota accounts with outbox-triggered snapshot refresh
- Display quota usage ($used / $limit) in account capacity column
- Add "Reset Quota" action in account menu to reset usage to zero
- Editing account settings preserves quota_used (no accidental reset)
- Covers all 3 billing paths: Anthropic, Gemini, OpenAI RecordUsage

chore: bump version to 0.1.90.4

backend/internal/handler/sora_client_handler_test.go

@@ -2132,6 +2132,14 @@ func (r *stubAccountRepoForHandler) BulkUpdate(context.Context, []int64, service
 	return 0, nil
 }
 
+func (r *stubAccountRepoForHandler) IncrementQuotaUsed(context.Context, int64, float64) error {
+	return nil
+}
+
+func (r *stubAccountRepoForHandler) ResetQuotaUsed(context.Context, int64) error {
+	return nil
+}
+
 // ==================== Stub: SoraClient (用于 SoraGatewayService) ====================
 
 var _ service.SoraClient = (*stubSoraClientForHandler)(nil)