Widen authorization-list nonce to hold full uint64 range

[ahmohamed]

Summary

• EIP-7702 authorization entries can carry a nonce of 2^64-1 on chain (the spec rejects them but they still land in blocks), and the existing BIGINT column on t_transaction_authorization_lists.f_nonce overflows when pgx encodes uint64 values that exceed int64.
• First observed at mainnet block 25060190, transaction 0xf0a1040198b59042cd218b899e010df69523e543ad4716f84d5d723230021d6b — one authorization entry with nonce=0xffffffffffffffff. execd stalled at block 25060189 with pgx errors unable to encode 0xffffffffffffffff into binary format for int8 (OID 20): 18446744073709551615 is greater than maximum value for int64.
• Adds schema migration v12 (widenAuthorizationListNonce) which ALTERs the column to NUMERIC(20,0). The fresh-install path in createTransactionAuthorizationLists is updated to match.
• Bumps ReleaseVersion to 0.6.1.