feat: set timezone space level

internal/model/space.go

@@ -13,10 +13,24 @@ type Space struct {
 	ID        string    `db:"id"`
 	Name      string    `db:"name"`
 	OwnerID   string    `db:"owner_id"`
+	Timezone  *string   `db:"timezone"`
 	CreatedAt time.Time `db:"created_at"`
 	UpdatedAt time.Time `db:"updated_at"`
 }
 
+// Location returns the *time.Location for this space's timezone.
+// Returns nil if timezone is not set, so callers can distinguish "not set" from "UTC".
+func (s *Space) Location() *time.Location {
+	if s.Timezone == nil || *s.Timezone == "" {
+		return nil
+	}
+	loc, err := time.LoadLocation(*s.Timezone)
+	if err != nil {
+		return nil
+	}
+	return loc
+}
+
 type SpaceMember struct {
 	SpaceID  string    `db:"space_id"`
 	UserID   string    `db:"user_id"`