Add Ballot Consistency Audit Report

[Just-Bamford]

��# Issue 16: Add Ballot Consistency Audit Report

Problem

No structured way to get full audit report. Requires multiple read calls to reconstruct state.

Solution

• Implement get_audit_report(ballot_id_hash) returning complete BallotAuditReport struct
• Report includes: created_at, admin, tokens_issued, votes_cast, result_hash, is_consistent, state
• TypeScript helper sorobanGetAuditReport() to fetch in single call
• Enables external verification and compliance audits

Implementation Tasks

• Define BallotAuditReport struct with all fields
• Implement get_audit_report() function assembling all data
• Add TypeScript helper sorobanGetAuditReport()
• Unit tests: report includes all required fields
• Unit tests: report matches individual reads
• Verify report is immutable (read-only)

Note for Contributors

Complete Issues #1, #9, #10, #12 (ballot metadata, state transitions, expiration, timestamps) first to have all report fields available. The audit report is a comprehensive snapshot of ballot state for compliance and verification purposes. Include all fields: created_at, admin, tokens_issued, votes_cast, result_hash, is_consistent flag, current state, expiration_time. This single function call replaces multiple read operations, improving efficiency. The report is read-only and immutable. Use this for external audits and compliance verification. Consider returning error if ballot doesn't exist (use Option or error type).

[wonder2778]

​I would like to work on this issue. I can implement the BallotAuditReport struct and its corresponding Soroban read function, with the TypeScript helper. I will make sure that all prerequisite data structures from issues #1, #9, #10, and #12 are aligned, and include full unit test coverage matching individual read