wallet: public_descriptors ignores the seed it's given #128

core_descriptors(secret, ...) calls BitcoinCore.public_descriptors and returns the descriptors of whatever HD key the named Core wallet holds. It only type-checks secret, so a wallet holding a different seed returns that wallet's descriptors.

Nothing needs this path: ms32 wallet gives Core the root xprv (addhdkey) and Core builds the descriptors (createwalletdescriptor). Pre-1.0, remove it rather than authenticate it.

Fix in #130:

• remove core_descriptors, WalletPublicDeriver and the unused descriptor-record path (codex32.__all__ drops to 22 names);
• remove the unused fresh Core Lightning generation exports; keep parsing, recovery and re-sharing of existing CL secrets;
• keep master_xprv and Wallet: use Core for setup and remove test crypto deps #7's Core-native account-0 setup; nonzero accounts stay in wallet: Support nonzero accounts with Core-native setup #68.

Absorbs #63 (same removal) and #64. Found by Codex review of #94, after the four supplied audit reports; not attributable to those reviewers.