Make mission -> mission launches one-to-many

src/MissionControl.Server/Endpoints/Missions/Contract.cs

@@ -15,7 +15,7 @@ public record MissionResponse
 
     public required DateTimeOffset CreatedAt { get; init; }
 
-    public MissionLaunchResponse? MissionLaunch { get; set; }
+    public IReadOnlyList<MissionLaunchResponse> MissionLaunches { get; set; } = [];
 
     public static MissionResponse FromDomain(Mission mission) =>
         new()
@@ -25,6 +25,6 @@ public record MissionResponse
             Description = mission.Description,
             Status = mission.Status,
             CreatedAt = mission.CreatedAt,
-            MissionLaunch = mission.MissionLaunch != null ? MissionLaunchResponse.FromDomain(mission.MissionLaunch) : null,
+            MissionLaunches = mission.MissionLaunches.Select(MissionLaunchResponse.FromDomain).ToList(),
         };
 }