chore(all): review error wrappings

- remove repetitive `cannot` and `failed` prefixes
- rename `unmarshaling` to `decoding`

internal/tun/create.go

@@ -22,18 +22,18 @@ func (t *Tun) Create(path string) error {
 	dev := unix.Mkdev(major, minor)
 	err := t.mknod(path, unix.S_IFCHR, int(dev))
 	if err != nil {
-		return fmt.Errorf("cannot create TUN device file node: %w", err)
+		return fmt.Errorf("creating TUN device file node: %w", err)
 	}
 
 	fd, err := unix.Open(path, 0, 0)
 	if err != nil {
-		return fmt.Errorf("cannot Unix Open TUN device file: %w", err)
+		return fmt.Errorf("unix opening TUN device file: %w", err)
 	}
 
 	const nonBlocking = true
 	err = unix.SetNonblock(fd, nonBlocking)
 	if err != nil {
-		return fmt.Errorf("cannot set non block to TUN device file descriptor: %w", err)
+		return fmt.Errorf("setting non block to TUN device file descriptor: %w", err)
 	}
 
 	return nil