feat: enhance Antigravity account overages handling and improve UI credit display

backend/internal/service/admin_service.go

@@ -1538,6 +1538,13 @@ func (s *adminServiceImpl) UpdateAccount(ctx context.Context, id int64, input *U
 			}
 		}
 		account.Extra = input.Extra
+		if account.Platform == PlatformAntigravity && wasOveragesEnabled && !account.IsOveragesEnabled() {
+			delete(account.Extra, antigravityCreditsOveragesKey)
+		}
+		if account.Platform == PlatformAntigravity && !wasOveragesEnabled && account.IsOveragesEnabled() {
+			delete(account.Extra, modelRateLimitsKey)
+			delete(account.Extra, antigravityCreditsOveragesKey)
+		}
 		// 校验并预计算固定时间重置的下次重置时间
 		if err := ValidateQuotaResetConfig(account.Extra); err != nil {
 			return nil, err
@@ -1623,9 +1630,6 @@ func (s *adminServiceImpl) UpdateAccount(ctx context.Context, id int64, input *U
 	if account.Platform == PlatformAntigravity {
 		if !account.IsOveragesEnabled() && wasOveragesEnabled {
 			clearCreditsExhausted(account.ID)
-			if err := clearAntigravityCreditsOveragesState(ctx, s.accountRepo, account.ID); err != nil {
-				return nil, err
-			}
 		}
 		if account.IsOveragesEnabled() && !wasOveragesEnabled {
 			clearCreditsExhausted(account.ID)

backend/internal/service/admin_service_overages_test.go

@@ -0,0 +1,111 @@
+//go:build unit
+
+package service
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+type updateAccountOveragesRepoStub struct {
+	mockAccountRepoForGemini
+	account     *Account
+	updateCalls int
+}
+
+func (r *updateAccountOveragesRepoStub) GetByID(ctx context.Context, id int64) (*Account, error) {
+	return r.account, nil
+}
+
+func (r *updateAccountOveragesRepoStub) Update(ctx context.Context, account *Account) error {
+	r.updateCalls++
+	r.account = account
+	return nil
+}
+
+func TestUpdateAccount_DisableOveragesClearsRuntimeStateBeforePersist(t *testing.T) {
+	accountID := int64(101)
+	repo := &updateAccountOveragesRepoStub{
+		account: &Account{
+			ID:       accountID,
+			Platform: PlatformAntigravity,
+			Type:     AccountTypeOAuth,
+			Status:   StatusActive,
+			Extra: map[string]any{
+				"allow_overages":   true,
+				"mixed_scheduling": true,
+				antigravityCreditsOveragesKey: map[string]any{
+					"claude-sonnet-4-5": map[string]any{
+						"activated_at": "2026-03-15T00:00:00Z",
+						"active_until": "2099-03-15T00:00:00Z",
+					},
+				},
+			},
+		},
+	}
+	setCreditsExhausted(accountID, time.Now().Add(time.Minute))
+	t.Cleanup(func() {
+		clearCreditsExhausted(accountID)
+	})
+
+	svc := &adminServiceImpl{accountRepo: repo}
+	updated, err := svc.UpdateAccount(context.Background(), accountID, &UpdateAccountInput{
+		Extra: map[string]any{
+			"mixed_scheduling": true,
+		},
+	})
+
+	require.NoError(t, err)
+	require.NotNil(t, updated)
+	require.Equal(t, 1, repo.updateCalls)
+	require.False(t, updated.IsOveragesEnabled())
+	require.False(t, isCreditsExhausted(accountID))
+
+	_, exists := repo.account.Extra[antigravityCreditsOveragesKey]
+	require.False(t, exists, "关闭 overages 时应在持久化前移除运行态")
+}
+
+func TestUpdateAccount_EnableOveragesClearsModelRateLimitsBeforePersist(t *testing.T) {
+	accountID := int64(102)
+	repo := &updateAccountOveragesRepoStub{
+		account: &Account{
+			ID:       accountID,
+			Platform: PlatformAntigravity,
+			Type:     AccountTypeOAuth,
+			Status:   StatusActive,
+			Extra: map[string]any{
+				"mixed_scheduling": true,
+				modelRateLimitsKey: map[string]any{
+					"claude-sonnet-4-5": map[string]any{
+						"rate_limited_at":     "2026-03-15T00:00:00Z",
+						"rate_limit_reset_at": "2099-03-15T00:00:00Z",
+					},
+				},
+			},
+		},
+	}
+	setCreditsExhausted(accountID, time.Now().Add(time.Minute))
+	t.Cleanup(func() {
+		clearCreditsExhausted(accountID)
+	})
+
+	svc := &adminServiceImpl{accountRepo: repo}
+	updated, err := svc.UpdateAccount(context.Background(), accountID, &UpdateAccountInput{
+		Extra: map[string]any{
+			"mixed_scheduling": true,
+			"allow_overages":   true,
+		},
+	})
+
+	require.NoError(t, err)
+	require.NotNil(t, updated)
+	require.Equal(t, 1, repo.updateCalls)
+	require.True(t, updated.IsOveragesEnabled())
+	require.False(t, isCreditsExhausted(accountID))
+
+	_, exists := repo.account.Extra[modelRateLimitsKey]
+	require.False(t, exists, "开启 overages 时应在持久化前清掉旧模型限流")
+}