Add e2e test for state-diff feature

Register EnableStateDiff and StateDiffExponents flags with the
beacon-chain CLI, and add an e2e test that runs with the state-diff
feature enabled.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

cmd/beacon-chain/main.go

@@ -156,6 +156,7 @@ var appFlags = []cli.Flag{
 	dasFlags.BackfillOldestSlot,
 	dasFlags.BlobRetentionEpochFlag,
 	flags.BatchVerifierLimit,
+	flags.StateDiffExponents,
 }
 
 func init() {

config/features/flags.go

@@ -270,6 +270,7 @@ var BeaconChainFlags = combinedFlags([]cli.Flag{
 	DisableQUIC,
 	EnableDiscoveryReboot,
 	enableExperimentalAttestationPool,
+	EnableStateDiff,
 	forceHeadFlag,
 	blacklistRoots,
 }, deprecatedBeaconFlags, deprecatedFlags, upcomingDeprecation)

testing/endtoend/BUILD.bazel

@@ -95,6 +95,7 @@ go_test(
         "endtoend_setup_test.go",
         "endtoend_test.go",
         "minimal_e2e_test.go",
+        "minimal_hdiff_e2e_test.go",
         "minimal_slashing_e2e_test.go",
         "slasher_simulator_e2e_test.go",
     ],

testing/endtoend/minimal_hdiff_e2e_test.go

@@ -0,0 +1,16 @@
+package endtoend
+
+import (
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v7/config/params"
+	"github.com/OffchainLabs/prysm/v7/runtime/version"
+	"github.com/OffchainLabs/prysm/v7/testing/endtoend/types"
+)
+
+func TestEndToEnd_MinimalConfig_WithStateDiff(t *testing.T) {
+	r := e2eMinimal(t, types.InitForkCfg(version.Bellatrix, version.Electra, params.E2ETestConfig()),
+		types.WithStateDiff(),
+	)
+	r.run()
+}

testing/endtoend/types/types.go

@@ -67,6 +67,15 @@ func WithSSZOnly() E2EConfigOpt {
 	}
 }
 
+func WithStateDiff() E2EConfigOpt {
+	return func(cfg *E2EConfig) {
+		cfg.BeaconFlags = append(cfg.BeaconFlags,
+			"--enable-state-diff",
+			"--state-diff-exponents=6,5", // Small exponents for quick testing
+		)
+	}
+}
+
 // E2EConfig defines the struct for all configurations needed for E2E testing.
 type E2EConfig struct {
 	TestCheckpointSync      bool