feat: add unit context to audit log format (#72)

[scottschreckengaust]

Summary

Adds unit-specific context to the audit.md logging format to improve traceability in multi-unit Construction phase workflows. Closes #72.

Changes

Two additive changes to aidlc-rules/aws-aidlc-rules/core-workflow.md:

1. Added a bullet to "Prompts Logging Requirements" specifying that Construction phase per-unit stages should include the unit name in the Context field.
2. Added an example block after the existing Audit Log Format template showing what a unit-context entry looks like.

User experience

Before: Audit log entries during multi-unit Construction lack unit identification, making it hard to trace which interactions belong to which unit.

After: Clear guidance and an example ensure unit names appear in the Context field (e.g., CONSTRUCTION - Code Generation - Unit: user-service).

Checklist

• I have reviewed the contributing guidelines
• I have performed a self-review of this change
• Changes have been tested
• Changes are documented

Test Plan

• Run a multi-unit AI-DLC workflow and verify audit.md entries include unit names in the Context field during Construction phase stages.
• Verify single-unit workflows are unaffected.

Acknowledgment

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of the project license.