Implement Soroban contract audit trail with query and export capabilities

[Just-Bamford]

Description

Problem

There is no standardized audit trail for contract invocation activity. Applications cannot easily reconstruct which account invoked a contract method, when the invocation occurred, which parameters were supplied, or whether the call succeeded.

This limits debugging, security investigations, and compliance workflows.

Solution

Create a structured contract audit subsystem that records invocation metadata without exposing sensitive values.

Audit entries should include caller identity, contract ID, function name, transaction ID, timestamp, execution status, duration, and sanitized argument metadata.

Provide filtering, pagination, and export capabilities.

Acceptance Criteria

• Contract invocations generate structured audit records.
• Records include caller, contract, function, transaction ID, timestamp, duration, and result status.
• Sensitive arguments can be redacted or excluded.
• queryContractAuditLog(filters) supports filtering.
• Queries support pagination and chronological ordering.
• Audit records can be exported as JSON and CSV.
• Failed and successful invocations are distinguishable.
• Tests cover logging, filtering, pagination, redaction, and export.
• Exported through src/soroban/index.ts and src/index.ts.

Note for Contributors

Audit logging should not materially change contract invocation latency. Avoid logging private keys, secrets, or complete sensitive payloads.

[dot-enny]

@dot-enny has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi there, I'd like to work on this please. Thank you.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @dot-enny to this issue.

[Turawa2]

@Turawa2 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I can work on this task , assign me please!

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Turawa2 to this issue.