feat: implemented team score handling

lib/data/models/match.dart

@@ -231,8 +231,13 @@ class Match {
   }
 
   List<Team> _getHighestScoreTeam() {
+    if (teams!.every((team) => team.score == null)) {
+      return [];
+    }
+
     final int highestScore = teams!
         .map((team) => team.score)
+        .whereType<int>()
         .reduce((max, score) => score > max ? score : max);
 
     return teams!.where((team) {
@@ -241,8 +246,13 @@ class Match {
   }
 
   List<Team> _getLowestScoreTeam() {
+    if (teams!.every((team) => team.score == null)) {
+      return [];
+    }
+
     final int lowestScore = teams!
         .map((team) => team.score)
+        .whereType<int>()
         .reduce((min, score) => score < min ? score : min);
 
     return teams!.where((team) {

lib/data/models/team.dart

@@ -9,7 +9,7 @@ class Team {
   final String name;
   final DateTime createdAt;
   final GameColor color;
-  final int score;
+  final int? score;
   final List<Player> members;
 
   Team({
@@ -17,7 +17,7 @@ class Team {
     required this.name,
     DateTime? createdAt,
     this.color = GameColor.blue,
-    this.score = 0,
+    this.score,
     required this.members,
   }) : id = id ?? const Uuid().v4(),
        createdAt = createdAt ?? clock.now();