[Feature Request] Support Jade signing for Simplicity `sighash_all` spends

[KyrylR]

We want to explore Jade support for signing Simplicity transactions

Current Simplicity P2PK:

lwk_simplicity/data/p2pk.simf:3

jet::bip_0340_verify((param::PUBLIC_KEY, jet::sig_all_hash()), witness::SIGNATURE)

The desired outcome is that LWK (or any other SDK) can construct a Simplicity P2PK spend where:

• PUBLIC_KEY is derived from a Jade-controlled key, as an x-only public key.
• Jade computes the Simplicity transaction sighash_all.
• Jade signs that 32-byte message with the matching key.
• The returned signature verifies as a BIP340 Schnorr signature.
• The signature satisfies the Simplicity program and the transaction can be finalized and broadcast.

Opening the issue for the discussion purposes, would appreciate any feedback and questions