Create ADR documenting the decision to use a monorepo structure with
service directories for organizing microservices (Option 1).
The ADR covers:
- Decision to use monorepo with service directories
- Rationale for monorepo vs separate repositories
- Proposed directory structure with cmd/ and services/
- Implementation strategy across epics
- Consequences and mitigations
- Migration path if needed in the future
This clarifies how services (Auth, Identity, Authz, Audit) should be
organized in the codebase while maintaining service independence and
microservices architecture principles.
