Implement Finale Echoing (Permanent)

- Sweeps and quests this game mode are not implemented yet

src/main/java/emu/nebula/server/handlers/HandlerJointDrill2ContinueReq.java

@@ -0,0 +1,37 @@
+package emu.nebula.server.handlers;
+
+import emu.nebula.net.NetHandler;
+import emu.nebula.net.NetMsgId;
+import emu.nebula.proto.JointDrill2Continue.JointDrill2ContinueReq;
+import emu.nebula.net.HandlerId;
+import emu.nebula.game.activity.type.JointDrillActivity;
+import emu.nebula.net.GameSession;
+
+@HandlerId(NetMsgId.joint_drill_2_continue_req)
+public class HandlerJointDrill2ContinueReq extends NetHandler {
+
+    @Override
+    public byte[] handle(GameSession session, byte[] message) throws Exception {
+        // Get joint drill activity
+        var activity = session.getPlayer().getActivityManager().getFirstActivity(JointDrillActivity.class);
+        
+        if (activity == null) {
+            return session.encodeMsg(NetMsgId.joint_drill_2_continue_failed_ack);
+        }
+        
+        // Parse request
+        var req = JointDrill2ContinueReq.parseFrom(message);
+        
+        // Continue
+        var success = activity.continueDrill(req.getBuildId());
+        
+        // Check
+        if (!success) {
+            return session.encodeMsg(NetMsgId.joint_drill_2_continue_failed_ack);
+        }
+        
+        // Encode and send
+        return session.encodeMsg(NetMsgId.joint_drill_2_continue_succeed_ack);
+    }
+
+}