test: token balances across multiple participant nodes

[dhyaniarun1993]

No description provided.

[gemini-code-assist]

Code Review

This pull request introduces a new test script, test-cip56-multi-participant.go, designed to validate CIP56 token balances across multiple Canton participants and issuers using external parties. The script automates synchronizer detection, party allocation, token configuration, and cross-participant balance verification. Review feedback identified significant issues with numeric handling, specifically pointing out that string-based trimming and float64 arithmetic are unsuitable for precise token balances; the use of math/big.Rat was recommended for all amount comparisons and summations. Additionally, suggestions were made to improve error handling during DAR file discovery and to clean up unused variables in the file-walking logic.