feat: decode ABI custom revert errors

[0xjc65eth]

Summary

• Decode ABI type: "error" entries when rendering trace/simulate revert output.
• Prefer decoded custom errors when revert data and contract ABI are available, falling back to the existing raw revert message otherwise.
• Add regression coverage for InsufficientShares(address,uint256,uint256) revert data.

Fixes #126.

Tests

• cargo test -p soldb-cli decodes_custom_error_revert_data_from_abi
• git diff --check