[BE-126] Expand access-logs module test coverage

[mftee]

Overview

backend/src/access-logs/ has one controller spec but the service, entity behaviour, and any interceptor are untested. Access logs are the audit trail for who viewed which land document — evidence that must be trustworthy.

Tasks

• Test the service layer: log creation, querying, and filtering by user, action, resource, and date range.
• Test that logs are append-only — no update or delete path should exist through the API.
• Test that a logging failure never breaks or rolls back the request being logged.
• Test that sensitive values (tokens, passwords, document contents) are redacted before persistence.
• Test pagination on the query endpoint.
• Target ≥75% coverage.

Acceptance Criteria

• Logs are proven immutable through the API.
• A logging failure is proven non-blocking.
• Redaction is covered by a test.

Notes for Contributors

Comment below to be assigned.