Extract the duplicated user-search business logic into two helpers both API
versions call, and refactor v1's handlers onto them:
- user.SearchUsers wraps ListUsers + email obfuscation (global search)
- models.SearchUsersForProject wraps the project read check + ListUsersFromProject
Each handler keeps its own forbidden mapping (v1 echo.ErrForbidden vs v2
huma) so v1 stays byte-identical on the wire.
This adds a feature where you can enable users to only find members of teams they're part of. This makes the user search when sharing projects less confusing, because users only see other users they already know.
It is still possible to add users to teams with their email address, if they have that enabled in the user settings.