[FEATURE] Build Project Details Endpoint for SMEUser

**Describe the solution you'd like**
Build an endpoint to allows a SMEUser:
- [ ] see a list of items they need to complete for the project to be marked as done

**IMPORTANT**
Write tests

Start by locating the SMEUser project routes and the existing endpoint test patterns. Clarify which project completion items must be returned and how completion is represented before implementing the endpoint. Done means the endpoint returns the required item list and tests cover its behavior.

Written by the indexing model from the issue text.