Add initial Capture the Flag plugin implementation

Implemented the core structure for a Capture the Flag (CTF) plugin. This includes team management, game phases, player classes, command handling, and configuration support. The project is set up with Gradle for dependency management and provides placeholders for future feature expansion.

src/main/java/com/alttd/ctf/team/TeamPlayer.java

@@ -0,0 +1,39 @@
+package com.alttd.ctf.team;
+
+import com.alttd.ctf.game_class.GameClass;
+import lombok.Getter;
+import lombok.Setter;
+
+import java.util.Objects;
+import java.util.UUID;
+
+@Getter
+public class TeamPlayer {
+
+    private final UUID uuid;
+    private final Team team;
+    @Setter
+    private GameClass gameClass;
+
+    protected TeamPlayer(UUID uuid, Team team) {
+        this.uuid = uuid;
+        this.team = team;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null || getClass() != obj.getClass()) {
+            return false;
+        }
+        TeamPlayer other = (TeamPlayer) obj;
+        return Objects.equals(uuid, other.uuid);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(uuid);
+    }
+}