Refactor player, event, RSVP, team, and ruleset list functions to initialize output slices with make([]Type, 0) for improved performance and clarity.

backend/internal/adapter/postgres/store.go

@@ -128,7 +128,7 @@ func (s *Store) ListPlayers(ctx context.Context) ([]domain.Player, error) {
 		return nil, err
 	}
 	defer rows.Close()
-	var out []domain.Player
+	out := make([]domain.Player, 0)
 	for rows.Next() {
 		var p domain.Player
 		var preferredRoles, preferredPlayers []byte
@@ -180,7 +180,7 @@ func (s *Store) ListEvents(ctx context.Context, from time.Time) ([]domain.Event,
 		return nil, err
 	}
 	defer rows.Close()
-	var out []domain.Event
+	out := make([]domain.Event, 0)
 	for rows.Next() {
 		var e domain.Event
 		if err := rows.Scan(&e.ID, &e.Name, &e.Description, &e.StartsAt, &e.EndsAt, &e.RegistrationDeadline, &e.CreatedBy, &e.CreatedAt, &e.UpdatedAt); err != nil {
@@ -207,7 +207,7 @@ func (s *Store) ListRSVPs(ctx context.Context, eventID string) ([]domain.RSVP, e
 		return nil, err
 	}
 	defer rows.Close()
-	var out []domain.RSVP
+	out := make([]domain.RSVP, 0)
 	for rows.Next() {
 		var r domain.RSVP
 		if err := rows.Scan(&r.EventID, &r.PlayerID, &r.Status, &r.ActorAccountID, &r.Source, &r.UpdatedAt); err != nil {
@@ -242,7 +242,7 @@ func (s *Store) ListTeams(ctx context.Context, eventID string) ([]domain.Team, e
 		return nil, err
 	}
 	defer rows.Close()
-	var out []domain.Team
+	out := make([]domain.Team, 0)
 	for rows.Next() {
 		var t domain.Team
 		var body []byte
@@ -287,7 +287,7 @@ func (s *Store) ListRulesets(ctx context.Context) ([]domain.Ruleset, error) {
 		return nil, err
 	}
 	defer rows.Close()
-	var rulesets []domain.Ruleset
+	rulesets := make([]domain.Ruleset, 0)
 	for rows.Next() {
 		var body []byte
 		var ruleset domain.Ruleset