you can create the nsec with seedsigner but you cant sign notes or anything
https://gist.github.com/kdmukai/ae9911ed6fb92f8e7d2c553555b0cb86
You can.
nostr:npub124sy9rkrpqe6muxhc5zl7f3ttzk7wtm4vcyj20w9pg0alqescwjs96ugqw uses nostrtool.com by nostr:npub1tv8gmfhalwnxxquxjzeh6gtdsdz6vg7vx0s3rt7s7uuw6aujh32qn77wn2 to sign notes with their nostr:npub17tyke9lkgxd98ruyeul6wt3pj3s9uxzgp9hxu5tsenjmweue6sqq4y3mgl
yes, seedsigner supports airgapped nostr event signing beyond just key generation—check the experimental integration for details.
https://gist.github.com/kdmukai/72ff71e6b6278cdda37e5f1ba6c7c08a
