feat(19-04): add users.handle, HandleGenerator and user.Created

Generate a unique mention handle on API register and admin create, and fire user.Created from both paths so listeners run in the same write.

Co-authored-by: Cursor <cursoragent@cursor.com>

controllers/api_controller.go

@@ -649,6 +649,7 @@ func Register(app *backpack.App) http.HandlerFunc {
 			return
 		}
 		_ = FireRegisterEvent(r.Context(), app, user, fields)
+		_ = FireCreatedEvent(r.Context(), app, user)
 		ctx := r.Context()
 		if mode == "user" {
 			vars := mailVars(displayName(user), "", "")

controllers/registration.go

@@ -77,6 +77,9 @@ func RegisterUser(ctx context.Context, app *backpack.App, db *gorm.DB, fields ma
 	if err := db.WithContext(ctx).Create(user).Error; err != nil {
 		return nil, nil, err
 	}
+	if err := classes.AssignHandle(ctx, db, user); err != nil {
+		return nil, nil, err
+	}
 	return user, nil, nil
 }
 
@@ -97,6 +100,16 @@ func FireRegisterEvent(ctx context.Context, app *backpack.App, user *models.User
 	return app.Events.Fire(ctx, &classes.RegisterEvent{User: user, Payload: payload})
 }
 
+// FireCreatedEvent fires classes.CreatedEvent (user.Created) for user and
+// returns the listeners' error. /register ignores that error, as it does
+// for FireRegisterEvent.
+func FireCreatedEvent(ctx context.Context, app *backpack.App, user *models.User) error {
+	if app == nil || app.Events == nil {
+		return nil
+	}
+	return app.Events.Fire(ctx, &classes.CreatedEvent{User: user})
+}
+
 // IssueToken mints the session JWT for user exactly as /register and
 // /login do: the plugin's JWT secret, golem15.user.jwt.ttl and the request
 // URL as the issuer.

controllers/users_admin_controller.go

@@ -302,23 +302,33 @@ func (c usersAdminController) storePassword(ctx context.Context, user *models.Us
 	return true, nil
 }
 
-// FormAfterCreate sends the invitation when the send_invite checkbox was
-// set: an activation code is issued inside the create's transaction, and
-// exactly one golem15.user::mail.invite message with the activation link
-// leaves after the commit. A create that rolls back sends nothing.
+// FormAfterCreate assigns a unique handle, fires user.Created
+// (CreatedEventName) inside the create transaction, and sends the
+// invitation when the send_invite checkbox was set: an activation code is
+// issued inside the same transaction, and exactly one
+// golem15.user::mail.invite message with the activation link leaves after
+// the commit. A create that rolls back sends nothing.
 func (c usersAdminController) FormAfterCreate(ctx context.Context, model any) error {
 	user, ok := model.(*models.User)
 	if !ok || user == nil {
 		return errors.New("users admin: form model is not a user")
 	}
-	values, _ := cabana.VirtualFieldsFromContext(ctx)
-	if invite, _ := values["send_invite"].(bool); !invite {
-		return nil
-	}
 	tx, ok := cabana.TxFromContext(ctx)
 	if !ok {
 		return errors.New("users admin: a create needs its transaction")
 	}
+	if err := classes.AssignHandle(ctx, tx.Session(&gorm.Session{NewDB: true}), user); err != nil {
+		return err
+	}
+	if app := c.application(); app != nil && app.Events != nil {
+		if err := app.Events.Fire(ctx, &classes.CreatedEvent{User: user, Tx: tx}); err != nil {
+			return fmt.Errorf("%s: %w", classes.CreatedEventName, err)
+		}
+	}
+	values, _ := cabana.VirtualFieldsFromContext(ctx)
+	if invite, _ := values["send_invite"].(bool); !invite {
+		return nil
+	}
 	code, err := classes.IssueActivationCode(ctx, tx.Session(&gorm.Session{NewDB: true}), user)
 	if err != nil {
 		return err