Feat/coinbase rotation

[average-gary]

Adds deterministic address derivation for coinbase outputs using HD wallet descriptors via miniscript crate. Each block found gets a fresh address derived from an extended public key.

This is ideal for privacy and QC resistance.

The code checks for /* in the descriptor via has_wildcard(). No wildcard = no rotation

New Config Options

# Only needed if using wildcard descriptor
coinbase_index_file = "/var/lib/pool/coinbase_index.dat"  # Required with wildcard
coinbase_start_index = 0  # Optional, defaults to 0

Existing configs work unchanged. Defaults preserve current behavior and coinbase_index_file = None means no rotation.

Testnet4 Validation

Two blocks mined on testnet4 (Jan 28, 2026):

• Index 4: tb1q5u4w9hwuepxfng9tusl5l0h353k32wuwv56s5x (block (https://mempool.space/testnet4/block/0000000000000000b2d658e434cb1383eb41853a1b8bb23df1993a6c9036f2f7))
• Index 5: tb1qlqym3pzn76qz5ecj7y36rwrgxrr83pnwxtc5rp (block (https://mempool.space/testnet4/block/00000000000000005a65b2d963bc3117c3b0f92d5674483e7ab6af1e03d51267))

Many more blocks have been found using this code. Any TN4 block with signature whirly-pool is a result of this rotation feature.

Blog: https://average-gary.github.io/sv2-apps/