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/autoetc.go

@@ -1,15 +1,12 @@
 package container
 
 import (
-	"encoding/gob"
 	"fmt"
 
 	"hakurei.app/check"
 	"hakurei.app/fhs"
 )
 
-func init() { gob.Register(new(AutoEtcOp)) }
-
 // Etc is a helper for appending [AutoEtcOp] to [Ops].
 func (f *Ops) Etc(host *check.Absolute, prefix string) *Ops {
 	e := &AutoEtcOp{prefix}