Function canUserEditTeam

canUserEditTeam(team_id: string, user_id: string): Promise<string | true>
Checks if a user has permission to edit a team.
Parameters
- team_id: string
  The ID of the team.
- user_id: string
  The ID of the user.
Returns Promise<string | true>

Returns true if the user can edit, or an error message if not.
- Defined in src/lib/server/teamService.ts:208