Services folder guidance

• Service modules for backend logic live here. Add/update Jest tests under test/interface/services to cover edge cases and integration points, keeping specs alongside the modules they validate; if a change cannot be tested meaningfully, document the rationale in the PR.
• Keep service APIs aligned with Express routes in ../server/routes and the Swagger spec in documentation/swagger.yaml.
• Ensure any agent-facing logic stays consistent with the IDs and roles defined in interface/server/ui/lib/agents.js.