feat(api): add description_templates to /systems/@me/settings

PluralKit.Core/Models/SystemConfig.cs

@@ -15,6 +15,7 @@ public class SystemConfig
     public bool ShowPrivateInfo { get; }
     public int? MemberLimitOverride { get; }
     public int? GroupLimitOverride { get; }
+    public ICollection<string> DescriptionTemplates { get; }
 
     public DateTimeZone Zone => DateTimeZoneProviders.Tzdb.GetZoneOrNull(UiTz);
 }
@@ -34,6 +35,8 @@ public static class SystemConfigExt
         o.Add("member_limit", cfg.MemberLimitOverride ?? Limits.MaxMemberCount);
         o.Add("group_limit", cfg.GroupLimitOverride ?? Limits.MaxGroupCount);
 
+        o.Add("description_templates", JArray.FromObject(cfg.DescriptionTemplates));
+
         return o;
     }
 }