container: enter init path early

There is generally no use case where any setup is required before init, and requiring the explicit function call is error-prone and unnecessary. It also causes trouble with packages using a similar trick. This change moves argv0 check early and makes it an import side effect. The stub will be removed in v0.5.

Signed-off-by: Ophestra <cat@gensokyo.uk>

container/initbind.go

@@ -1,7 +1,6 @@
 package container
 
 import (
-	"encoding/gob"
 	"fmt"
 	"os"
 	"syscall"
@@ -10,8 +9,6 @@ import (
 	"hakurei.app/container/std"
 )
 
-func init() { gob.Register(new(BindMountOp)) }
-
 // Bind is a helper for appending [BindMountOp] to [Ops].
 func (f *Ops) Bind(source, target *check.Absolute, flags int) *Ops {
 	*f = append(*f, &BindMountOp{nil, source, target, flags})