feat(settings): simplify team management into flat teams and groups

frontend/src/lib/api.ts

@@ -664,6 +664,13 @@ export const api = {
     });
   },
 
+  async createTeam(name: string, description = ''): Promise<Team> {
+    return request<Team>('/api/v1/teams', {
+      method: 'POST',
+      body: JSON.stringify({ name, description }),
+    });
+  },
+
   async deleteTeam(teamId: string): Promise<void> {
     await request(`/api/v1/teams/${teamId}`, { method: 'DELETE' });
   },