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

backend/internal/service/sticky_session_test.go

@@ -23,32 +23,90 @@ import (
 //   - 临时不可调度且未过期：清理
 //   - 临时不可调度已过期：不清理
 //   - 正常可调度状态：不清理
+//   - 模型限流超过阈值：清理
+//   - 模型限流未超过阈值：不清理
 //
 // TestShouldClearStickySession tests the sticky session clearing logic.
 // Verifies correct behavior for various account states including:
-// nil account, error/disabled status, unschedulable, temporary unschedulable.
+// nil account, error/disabled status, unschedulable, temporary unschedulable,
+// and model rate limiting scenarios.
 func TestShouldClearStickySession(t *testing.T) {
 	now := time.Now()
 	future := now.Add(1 * time.Hour)
 	past := now.Add(-1 * time.Hour)
 
+	// 短限流时间（低于阈值，不应清除粘性会话）
+	shortRateLimitReset := now.Add(5 * time.Second).Format(time.RFC3339)
+	// 长限流时间（超过阈值，应清除粘性会话）
+	longRateLimitReset := now.Add(30 * time.Second).Format(time.RFC3339)
+
 	tests := []struct {
-		name    string
-		account *Account
-		want    bool
+		name           string
+		account        *Account
+		requestedModel string
+		want           bool
 	}{
-		{name: "nil account", account: nil, want: false},
-		{name: "status error", account: &Account{Status: StatusError, Schedulable: true}, want: true},
-		{name: "status disabled", account: &Account{Status: StatusDisabled, Schedulable: true}, want: true},
-		{name: "schedulable false", account: &Account{Status: StatusActive, Schedulable: false}, want: true},
-		{name: "temp unschedulable", account: &Account{Status: StatusActive, Schedulable: true, TempUnschedulableUntil: &future}, want: true},
-		{name: "temp unschedulable expired", account: &Account{Status: StatusActive, Schedulable: true, TempUnschedulableUntil: &past}, want: false},
-		{name: "active schedulable", account: &Account{Status: StatusActive, Schedulable: true}, want: false},
+		{name: "nil account", account: nil, requestedModel: "", want: false},
+		{name: "status error", account: &Account{Status: StatusError, Schedulable: true}, requestedModel: "", want: true},
+		{name: "status disabled", account: &Account{Status: StatusDisabled, Schedulable: true}, requestedModel: "", want: true},
+		{name: "schedulable false", account: &Account{Status: StatusActive, Schedulable: false}, requestedModel: "", want: true},
+		{name: "temp unschedulable", account: &Account{Status: StatusActive, Schedulable: true, TempUnschedulableUntil: &future}, requestedModel: "", want: true},
+		{name: "temp unschedulable expired", account: &Account{Status: StatusActive, Schedulable: true, TempUnschedulableUntil: &past}, requestedModel: "", want: false},
+		{name: "active schedulable", account: &Account{Status: StatusActive, Schedulable: true}, requestedModel: "", want: false},
+		// 模型限流测试
+		{
+			name: "model rate limited short duration",
+			account: &Account{
+				Status:      StatusActive,
+				Schedulable: true,
+				Extra: map[string]any{
+					"model_rate_limits": map[string]any{
+						"claude-sonnet-4": map[string]any{
+							"rate_limit_reset_at": shortRateLimitReset,
+						},
+					},
+				},
+			},
+			requestedModel: "claude-sonnet-4",
+			want:           false, // 低于阈值，不清除
+		},
+		{
+			name: "model rate limited long duration",
+			account: &Account{
+				Status:      StatusActive,
+				Schedulable: true,
+				Extra: map[string]any{
+					"model_rate_limits": map[string]any{
+						"claude-sonnet-4": map[string]any{
+							"rate_limit_reset_at": longRateLimitReset,
+						},
+					},
+				},
+			},
+			requestedModel: "claude-sonnet-4",
+			want:           true, // 超过阈值，清除
+		},
+		{
+			name: "model rate limited different model",
+			account: &Account{
+				Status:      StatusActive,
+				Schedulable: true,
+				Extra: map[string]any{
+					"model_rate_limits": map[string]any{
+						"claude-sonnet-4": map[string]any{
+							"rate_limit_reset_at": longRateLimitReset,
+						},
+					},
+				},
+			},
+			requestedModel: "claude-opus-4", // 请求不同模型
+			want:           false,           // 不同模型不受影响
+		},
 	}
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			require.Equal(t, tt.want, shouldClearStickySession(tt.account))
+			require.Equal(t, tt.want, shouldClearStickySession(tt.account, tt.requestedModel))
 		})
 	}
 }