feat: complete 4×64-bit LongArray migration — 167/167 secp256k1 tests pass
All secp256k1 tests pass with the new 4×64-bit limb representation:
- U256: 25/25 pass (mulWide, sqrWide with unsignedMultiplyHigh)
- FieldP: 27/27 pass (reduceWide using unsignedMultiplyHigh for C-multiply)
- ScalarN: 19/19 pass (reduceWide with correct unsigned overflow handling)
- Glv: 14/14 pass (wNAF encoding with 64-bit limb bit manipulation)
- Point: 22/22 pass (comb method, Strauss, all scalar mul strategies)
- Schnorr: 22/22 pass (all BIP-340 test vectors)
- Secp256k1: 20/20 pass (key ops, ECDH, sign/verify)
- KeyCodec: 18/18 pass
One downstream failure: NIP-44 conversation key vector 32 (scalar n-8)
needs investigation — likely a ScalarN edge case in GLV decomposition.
https://claude.ai/code/session_01BhU63WUe9AhikZxRdw3Lpg
Claude
cb1e8be529