feat: Authors feature backend (and upgraded deprecated mods)

api/handlers/activity/activityHandler.go

@@ -29,7 +29,7 @@ type Handler struct {
 type filterQuery struct {
 	Q        string `validate:"max=200"`
 	Actor    string `validate:"max=40"`
-	Category string `validate:"omitempty,oneof=articles media users api_keys auth system sites"`
+	Category string `validate:"omitempty,oneof=articles media users api_keys auth system sites authors"`
 	Outcome  string `validate:"omitempty,oneof=all success failed"`
 	Security string `validate:"omitempty,oneof=true"`
 	Range    string `validate:"omitempty,oneof=today 7d 30d all custom"`