Config: Add Isthmus to Hard fork config

add the upcoming Isthmus hard fork to config

superchain/superchain.go

@@ -61,6 +61,7 @@ type HardForkConfiguration struct {
 	FjordTime    *uint64 `json:"fjord_time,omitempty" toml:"fjord_time,omitempty"`
 	GraniteTime  *uint64 `json:"granite_time,omitempty" toml:"granite_time,omitempty"`
 	HoloceneTime *uint64 `json:"holocene_time,omitempty" toml:"holocene_time,omitempty"`
+	IsthmusTime  *uint64 `json:"isthmus_time,omitempty" toml:"isthmus_time,omitempty"`
 }
 
 type SuperchainLevel uint
@@ -265,6 +266,7 @@ func (c *ChainConfig) GenerateTOMLComments(ctx context.Context) (map[string]stri
 	createTimestampComment("fjord_time", c.FjordTime, comments)
 	createTimestampComment("granite_time", c.GraniteTime, comments)
 	createTimestampComment("holocene_time", c.HoloceneTime, comments)
+	createTimestampComment("isthmus_time", c.IsthmusTime, comments)
 
 	if c.StandardChainCandidate {
 		comments["standard_chain_candidate"] = "# This is a temporary field which causes most of the standard validation checks to run on this chain"

superchain/superchain_test.go

@@ -198,6 +198,10 @@ op_contracts_manager_proxy_addr = "0xF564eEA7960EA244bfEbCBbB17858748606147bf"
 canyon_time = 1
 delta_time = 2
 ecotone_time = 3
+fjord_time = 4
+granite_time = 5
+holocene_time = 6
+isthmus_time = 7
 
 [l1]
   chain_id = 314
@@ -223,7 +227,10 @@ ecotone_time = 3
 	require.Equal(t, uint64Ptr(uint64(1)), s.hardForkDefaults.CanyonTime)
 	require.Equal(t, uint64Ptr(uint64(2)), s.hardForkDefaults.DeltaTime)
 	require.Equal(t, uint64Ptr(uint64(3)), s.hardForkDefaults.EcotoneTime)
-	require.Nil(t, s.hardForkDefaults.FjordTime)
+	require.Equal(t, uint64Ptr(uint64(4)), s.hardForkDefaults.FjordTime)
+	require.Equal(t, uint64Ptr(uint64(5)), s.hardForkDefaults.GraniteTime)
+	require.Equal(t, uint64Ptr(uint64(6)), s.hardForkDefaults.HoloceneTime)
+	require.Equal(t, uint64Ptr(uint64(7)), s.hardForkDefaults.IsthmusTime)
 }
 
 func TestHardForkOverridesAndDefaults(t *testing.T) {