feat(admin): reset a user's recommendations from the users panel

- POST /admin/users/{id}/reset-recommendations clears the taste profile
  (onboarding, CF vector, bandit), play stats and wave impressions; likes,
  dislikes and history stay, wave sessions stay so a playing wave keeps going
- moderators may reset plain users, admins anyone including themselves;
  the reset is written to the audit log
- users panel gets the menu action with a confirmation; docs updated

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

services/api/internal/auth/admin.go

@@ -290,6 +290,25 @@ func (s *Service) ResetPassword(ctx context.Context, p Principal, id uuid.UUID)
 	return password, nil
 }
 
+// ResetRecommendations начинает рекомендации пользователя с нуля; онбординг покажется снова.
+func (s *Service) ResetRecommendations(ctx context.Context, p Principal, id uuid.UUID) error {
+	return s.store.WithTx(ctx, func(tx Store) error {
+		target, err := s.target(ctx, tx, id)
+		if err != nil {
+			return err
+		}
+		if !CanManageUser(actorOf(p), actorOfUser(target), UserResetRecommendations) {
+			return forbidden()
+		}
+		if err := tx.ResetRecommendations(ctx, target.ID); err != nil {
+			return err
+		}
+		return tx.InsertAudit(ctx, s.ids.New(), AuditEntry{
+			ActorID: &p.UserID, Action: "user.recommendations_reset", TargetType: "user", TargetID: &target.ID,
+		})
+	})
+}
+
 // DeleteUser удаляет пользователя (только админ, не себя и не последнего админа).
 func (s *Service) DeleteUser(ctx context.Context, p Principal, id uuid.UUID) error {
 	return s.store.WithTx(ctx, func(tx Store) error {