fix(gateway): harden digest logging and align antigravity ops

- avoid panic by using safe UUID prefix truncation in Gemini digest fallback logs\n- remove unconditional Antigravity 429 full-body debug logs and honor log truncation config\n- align Antigravity quick preset mappings to opus 4.6-thinking targets only\n- restore scope rate-limit aggregation/output in ops availability stats

backend/internal/service/ops_account_availability.go

@@ -66,6 +66,7 @@ func (s *OpsService) GetAccountAvailabilityStats(ctx context.Context, platformFi
 		}
 
 		isAvailable := acc.Status == StatusActive && acc.Schedulable && !isRateLimited && !isOverloaded && !isTempUnsched
+		scopeRateLimits := acc.GetAntigravityScopeRateLimits()
 
 		if acc.Platform != "" {
 			if _, ok := platform[acc.Platform]; !ok {
@@ -84,6 +85,14 @@ func (s *OpsService) GetAccountAvailabilityStats(ctx context.Context, platformFi
 			if hasError {
 				p.ErrorCount++
 			}
+			if len(scopeRateLimits) > 0 {
+				if p.ScopeRateLimitCount == nil {
+					p.ScopeRateLimitCount = make(map[string]int64)
+				}
+				for scope := range scopeRateLimits {
+					p.ScopeRateLimitCount[scope]++
+				}
+			}
 		}
 
 		for _, grp := range acc.Groups {
@@ -108,6 +117,14 @@ func (s *OpsService) GetAccountAvailabilityStats(ctx context.Context, platformFi
 			if hasError {
 				g.ErrorCount++
 			}
+			if len(scopeRateLimits) > 0 {
+				if g.ScopeRateLimitCount == nil {
+					g.ScopeRateLimitCount = make(map[string]int64)
+				}
+				for scope := range scopeRateLimits {
+					g.ScopeRateLimitCount[scope]++
+				}
+			}
 		}
 
 		displayGroupID := int64(0)
@@ -140,6 +157,9 @@ func (s *OpsService) GetAccountAvailabilityStats(ctx context.Context, platformFi
 				item.RateLimitRemainingSec = &remainingSec
 			}
 		}
+		if len(scopeRateLimits) > 0 {
+			item.ScopeRateLimits = scopeRateLimits
+		}
 		if isOverloaded && acc.OverloadUntil != nil {
 			item.OverloadUntil = acc.OverloadUntil
 			remainingSec := int64(time.Until(*acc.OverloadUntil).Seconds())