all: make timestamp-based fork checks based on uint64 (#26474)

This PR changes the API so that uint64 is used for fork timestamps.
It's a good choice because types.Header also uses uint64 for time.

Co-authored-by: Felix Lange <fjl@twurst.com>

cmd/geth/config.go

@@ -159,7 +159,8 @@ func makeConfigNode(ctx *cli.Context) (*node.Node, gethConfig) {
 func makeFullNode(ctx *cli.Context) (*node.Node, ethapi.Backend) {
 	stack, cfg := makeConfigNode(ctx)
 	if ctx.IsSet(utils.OverrideShanghai.Name) {
-		cfg.Eth.OverrideShanghai = flags.GlobalBig(ctx, utils.OverrideShanghai.Name)
+		v := ctx.Uint64(utils.OverrideShanghai.Name)
+		cfg.Eth.OverrideShanghai = &v
 	}
 	backend, eth := utils.RegisterEthService(stack, &cfg.Eth)