actually the alby extension does that. there you have a master key from which the nostr key is derived.
nobody even implements nip-06 except in a few libraries but no apps i know of
cc: nostr:nprofile1qyt8wumn8ghj7etyv4hzumn0wd68ytnvv9hxgtcppemhxue69uhkummn9ekx7mp0qy08wumn8ghj7mn0wd68yttsw43zuam9d3kx7unyv4ezumn9wshszythwden5te0dehhxarj9emkjmn99uq3xamnwvaz7tmsw4e8qmr9wpskwtn9wvhsz9thwden5te0wfjkccte9ejxzmt4wvhxjme0qythwumn8ghj7un9d3shjtnwdaehgu3wvfskuep0qqsrxra3gv0lnkxz2pcxh0xuq9k4f9dr7azwq3aypqtnay4w0mjzmtq8hdu63 would be cool if you supported BIP-39 nip-06 keys so people can more easily back them up offline
they are supported in the alby hub, and yes btw i am now using it
Discussion
i didn't say HD key i said BIP-39 word-mnemonic-key
reminds me, i should actually revise my key miner to print out the 24 word BIP39 with the keys
i was gonna play games this evening but games bore me far more than writing code
this all made me realise there isn't a deterministic encoding scheme
24 words from 2048 word dictionary is actually 264 bits which is a full key plus a byte of check
i'm going to draft a scheme based on the bip39, this is an easy implementation and try to get some traction on it
no cold backup for nostr keys is wrawwwngg