Fetch a group's details by tag. This works for private groups too.
Auth: None.
GET /v2/groups/mygroupResponse 200: a group object.
{
"id": "550e8400-e29b-41d4-a716-446655440000",
"tag": "mygroup",
"name": "My Group",
"description": "A group for testing",
"readme": "# About\nWelcome to our group.",
"rules": "1. Be respectful\n2. No spam",
"icon_url": "https://api.rotur.dev/groups/mygroup/icon.jpg",
"banner_url": "https://api.rotur.dev/groups/mygroup/banner",
"owner_user_id": "alice",
"public": true,
"join_policy": "OPEN",
"entry_fee": 5.0,
"created_at": 1717000000,
"credits_balance": 75.5,
"member_count": 12
}