refactor: deprecate int32 (#7025)

* refactor: deprecate int32

* fix(db): reject legacy user quota schemas at startup

* fix(quota): enforce wallet bounds and saturating billing conversions

* fix(rate-limit): keep count*duration from wrapping int64

* fix: error message

model/redemption_test.go

@@ -148,6 +148,35 @@ func TestRedeemCreditsQuotaExactlyOnce(t *testing.T) {
 	assert.Equal(t, 500, user.Quota)
 }
 
+func TestRedeemRejectsWalletOverflow(t *testing.T) {
+	userId, key := setupRedeemFixture(t, 11)
+	require.NoError(t, DB.Model(&User{}).Where("id = ?", userId).Update("quota", common.MaxWalletQuota-10).Error)
+
+	_, err := Redeem(key, userId)
+	require.ErrorIs(t, err, ErrRedeemFailed)
+
+	var user User
+	require.NoError(t, DB.First(&user, "id = ?", userId).Error)
+	assert.Equal(t, common.MaxWalletQuota-10, user.Quota)
+
+	var redemption Redemption
+	require.NoError(t, DB.First(&redemption, "key = ?", key).Error)
+	assert.Equal(t, common.RedemptionCodeStatusEnabled, redemption.Status)
+}
+
+func TestRedemptionQuotaRejectsWalletOverflow(t *testing.T) {
+	setupRedeemFixture(t, 500)
+
+	redemption := &Redemption{
+		Name:        "overflow-redemption",
+		Key:         "10000000000000000000000000000002",
+		Status:      common.RedemptionCodeStatusEnabled,
+		Quota:       common.MaxWalletQuota + 1,
+		CreatedTime: common.GetTimestamp(),
+	}
+	require.Error(t, redemption.Insert())
+}
+
 // Exactly one of several concurrent redeems of the same code may win, and
 // quota must be credited exactly once.
 func TestRedeemConcurrentSingleSuccess(t *testing.T) {