Taigam, Master Opportunist - Server Crash

Game crashed when casting Taigam and then a second spell

```
Error type: SERVER - game error

Client version: 1.4.58-V1 (build: 2025-10-06 20:20)
Java version: 1.8.0_201
Default charset: UTF-8

Game end on critical error: mage.MageException: Error in unit tests

mage.MageException: Error in unit tests
Server version: 1.4.58-V1 (build: 2025-10-06 20:20)
Stack trace:
mage.game.GameImpl.playPriority(GameImpl.java:1816)
mage.game.turn.Step.priority(Step.java:73)
mage.game.turn.Phase.playStep(Phase.java:205)
mage.game.turn.Phase.play(Phase.java:91)
mage.game.turn.Turn.play(Turn.java:132)
mage.game.GameImpl.playTurn(GameImpl.java:1183)
mage.game.GameImpl.play(GameImpl.java:1090)
mage.game.GameImpl.start(GameImpl.java:1066)
mage.server.game.GameWorker.call(GameWorker.java:35)
mage.server.game.GameWorker.call(GameWorker.java:16)
java.util.concurrent.FutureTask.run(FutureTask.java:266)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
java.lang.Thread.run(Thread.java:750)

```

Reproduce the crash by casting Taigam and then a second spell, then start at mage.game.GameImpl.playPriority and follow the priority flow through Step.java and Phase.java. Compare the failing path with the Taigam card behavior and add a regression test if the relevant test location can be identified. Done means the same sequence completes without a server crash.

Written by the indexing model from the issue text.