fix(rules): apply the -2 spell combat penalty to melee attacks

PF1e CRB (Magus Spell Combat): as a full-round action the magus casts a
standard-action spell and makes all his melee attacks at -2. The penalty is
threaded through the full-attack chain (_execute_attack -> _full_attack ->
_full_attack_weapon -> _attack/_resolve_swing -> resolve_attack bonus_override)
so it applies to every attack roll and crit confirmation. Simplification: the
arcane pool cost is still not modeled.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

tests/test_class_abilities.py

@@ -336,3 +336,42 @@ def test_misty_silent_when_bardic_rounds_exhausted() -> None:
 
     assert not any(a.kind == "inspire_courage" for a in actions)
     assert not any(a.kind == "spell_combat" for a in actions)
+
+
+def test_spell_combat_melee_attacks_take_minus_two() -> None:
+    """CRB Magus Spell Combat: the full attack that accompanies the cast is
+    made at -2 on every attack roll (vs the same swing in a normal full attack)."""
+    misty = _combatant(
+        "misty", resources={"bardic_rounds": 12}, spells=["Create Alcool"]
+    )
+    goblin = _combatant("goblin", hp_max=6)
+    reg = load_spell_registry(SPELLS_DIR)
+    # Queue: goblin AoO d20 (natural 1, auto-miss), then misty's swing d20=10.
+    engine, me, enemy = _engine(misty, [goblin], spell_registry=reg, rng_queue=[1, 10])
+
+    engine._execute(
+        me,
+        Action(
+            kind="spell_combat", target_id=enemy[0].combatant.id,
+            spell_name="Create Alcool",
+        ),
+    )
+
+    # Sword attack_bonus 3 + Spell Combat -2 = +1: d20 10 -> total 11 (misses AC 15).
+    assert any(
+        "sword vs goblin d20=10+1=11" in line for line in engine._transcript
+    )
+
+
+def test_normal_full_attack_has_no_spell_combat_penalty() -> None:
+    """Control: the same scripted swing in a plain full attack keeps its +3."""
+    misty = _combatant("misty", resources={"bardic_rounds": 12})
+    goblin = _combatant("goblin", hp_max=6)
+    reg = load_spell_registry(SPELLS_DIR)
+    engine, me, enemy = _engine(misty, [goblin], spell_registry=reg, rng_queue=[10])
+
+    engine._execute(me, Action(kind="full_attack", target_id=enemy[0].combatant.id))
+
+    assert any(
+        "sword vs goblin d20=10+3=13" in line for line in engine._transcript
+    )