- ResolvedMember record in Core/Models with DisplayName and Login
- ISharePointGroupResolver interface with ResolveGroupsAsync contract
- SharePointGroupResolver: CSOM group user loading + Graph transitive AAD resolution
- Internal static helpers IsAadGroup, ExtractAadGroupId, StripClaims (all green unit tests)
- Graceful error handling: exceptions return empty list per group, never throw
- OrdinalIgnoreCase result dict; lazy Graph client creation on first AAD group
