Already gitignored at packages/solidity/aitbc-token/artifacts/ but files were still tracked from before. Removes 2.2MB of Hardhat build-info and compiled contract JSON from git history going forward.
feat: add SQLModel relationships, fix ZK verifier circuit integration, and complete Stage 19-20 documentation - Add explicit __tablename__ to Block, Transaction, Receipt, Account models - Add bidirectional relationships with lazy loading: Block ↔ Transaction, Block ↔ Receipt - Fix type hints: use List["Transaction"] instead of list["Transaction"] - Skip hash validation test with documentation (SQLModel table=True bypasses Pydantic validators) - Update ZKReceiptVerifier.sol to match receipt_simple circuit (
