fix(cmd): wire --bintrie.groupdepth flag to SetEthConfig (#571)

The --bintrie.groupdepth CLI flag was defined and registered but never
read by SetEthConfig(), which is the main config path for geth node
startup. Only MakeChain() (used for import/export commands) read the
flag. This caused geth to always use the default groupDepth=8 regardless
of the CLI flag value.

This resulted in a serialization format mismatch when state-actor
generated databases with groupDepth != 8: state-actor wrote nodes with
the requested groupDepth (e.g. 1), but geth always read/wrote them
with groupDepth=8, causing "missing trie node" errors during block
validation.

The fix adds the flag read to SetEthConfig, matching the pattern used
by all other trie configuration flags (StateHistory, TrienodeHistory,
etc.).

cmd/utils/flags.go

@@ -1817,6 +1817,9 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *ethconfig.Config) {
 	if ctx.IsSet(TrienodeHistoryFullValueCheckpointFlag.Name) {
 		cfg.TrienodeHistory = ctx.Int64(TrienodeHistoryFullValueCheckpointFlag.Name)
 	}
+	if ctx.IsSet(BinTrieGroupDepthFlag.Name) {
+		cfg.BinTrieGroupDepth = ctx.Int(BinTrieGroupDepthFlag.Name)
+	}
 	if ctx.IsSet(StateSchemeFlag.Name) {
 		cfg.StateScheme = ctx.String(StateSchemeFlag.Name)
 	}