fix(rules): restricted charge - a creature limited to a standard action (staggered/disabled, surprise round) can still charge at 1x speed

tests/test_charge_result.py

@@ -205,6 +205,31 @@ def test_charge_result_no_charge_path_too_far() -> None:
     assert result.distance_ft == 0
 
 
+def test_restricted_charge_halves_the_budget() -> None:
+    """SRD "Charge": a creature able to take only a standard action (here a
+    disabled one at 0 hp) can still charge, but only up to its speed (1x,
+    6 cells at 30 ft) instead of double speed — a target 6 cells away stays
+    chargeable, one 10 cells away is not."""
+    a = make_state(make_combatant("a"), "players", (0, 0))
+    near = make_state(make_combatant("near"), "monsters", (0, 6))
+    engine = make_engine([a, near], make_grid(12))
+    a.hp = 0  # disabled -> staggered -> restricted charge
+    result = engine.can_charge(a, near)
+    assert isinstance(result, ChargeResult)
+    assert result.weapon is not None  # end cell 5 steps away <= 1x budget
+    a2 = make_state(make_combatant("a2"), "players", (0, 0))
+    far = make_state(make_combatant("far"), "monsters", (0, 10))
+    engine2 = make_engine([a2, far], make_grid(12))
+    a2.hp = 0
+    res2 = engine2.can_charge(a2, far)
+    assert isinstance(res2, ChargeResult)
+    assert res2.weapon is None  # 9 steps to the closest attack cell needs 2x
+    a2.hp = 20  # standing again: full 2x charge is legal
+    res3 = engine2.can_charge(a2, far)
+    assert isinstance(res3, ChargeResult)
+    assert res3.weapon is not None
+
+
 # --- Test 5: no melee weapon -------------------------------------------------