✅ Marchosias shield slam status expires after phase

Category	Ability
Status	Passing
Test	tests/test_abilities_actions.py::test_marchosias_shield_slam_status_expires_after_phase

Shield Slam statuses expire at end of main phase.

Preconditions

• After Shield Slam: Flauros has "pwr" -2, Marchosias has "def" +3 (phase_counter=1)

Action

• Advance phase_counter to 2, call expire_status_effects()

result = execute_ability(state, marchosias_on_field, ability_idx=1, targets=[flauros_on_field])
    result.phase_counter += 1
    result = expire_status_effects(result)

Expected Postconditions

• No active status effects on Flauros or Marchosias

Assertions

assert len(flauros_effects_after) == 0
    assert len(marchosias_effects_after) == 0