fix(rules): apply the spell combat penalty to the spell attack

PF1e (CRB Magus Spell Combat): "any attack roll made as part of this
spell also takes this penalty". _execute_spell_combat now threads the -2
through _cast_spell into the melee/ranged touch attack helpers, so e.g.
Shocking Grasp delivered via Spell Combat attacks at -2 too. No global
state is touched: the penalty is a keyword threaded per cast.

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

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

tests/test_class_abilities.py

@@ -31,6 +31,7 @@ def _combatant(
     *,
     resources: dict[str, int] | None = None,
     spells: list[str] | None = None,
+    spell_slots: dict[str, int] | None = None,
     hp_max: int = 20,
     creature_type: Literal["living", "undead", "construct"] = "living",
 ) -> Combatant:
@@ -59,6 +60,7 @@ def _combatant(
         attacks=[attack],
         resources=resources or {},
         spells=spells or [],
+        spell_slots=spell_slots or {},
         creature_type=creature_type,
     )
 
@@ -378,6 +380,56 @@ def test_normal_full_attack_has_no_spell_combat_penalty() -> None:
     )
 
 
+def test_spell_combat_penalty_applies_to_spell_touch_attack() -> None:
+    """CRB Magus Spell Combat: "any attack roll made as part of this spell
+    also takes this penalty" — Shocking Grasp's melee touch attack is at -2
+    (bab 3 + str 2 - 2 = +3): d20 8 -> 11 misses touch AC 12, so the spell
+    is wasted. Without the penalty the same roll (8+5=13) would have hit."""
+    misty = _combatant(
+        "misty", resources={"bardic_rounds": 12}, spells=["Shocking Grasp"],
+        spell_slots={1: 1},
+    )
+    goblin = _combatant("goblin", hp_max=6)
+    reg = load_spell_registry(SPELLS_DIR)
+    # Queue: goblin AoO on the cast (nat 1 miss), touch d20=8, swing d20=10.
+    engine, me, enemy = _engine(
+        misty, [goblin], spell_registry=reg, rng_queue=[1, 8, 10]
+    )
+    engine._execute(
+        me,
+        Action(
+            kind="spell_combat", target_id=enemy[0].combatant.id,
+            spell_name="Shocking Grasp",
+        ),
+    )
+    assert any(
+        "touch attack vs goblin d20=8+3=11 AC 12 -> MISS" in line
+        for line in engine._transcript
+    )
+    assert enemy[0].hp == 6  # the missed touch delivers no electricity
+
+
+def test_plain_cast_touch_attack_has_no_spell_combat_penalty() -> None:
+    """Control: the same Shocking Grasp cast through cast_spell keeps +5
+    (bab 3 + str 2): d20 8 -> 13 hits touch AC 12 and deals damage."""
+    misty = _combatant(
+        "misty", spells=["Shocking Grasp"], spell_slots={1: 1}
+    )
+    goblin = _combatant("goblin", hp_max=6)
+    reg = load_spell_registry(SPELLS_DIR)
+    # Queue: goblin AoO (nat 1 miss), touch d20=8, damage 1d6=4.
+    engine, me, enemy = _engine(misty, [goblin], spell_registry=reg, rng_queue=[1, 8, 4])
+    engine._execute(
+        me, Action(kind="cast_spell", target_id=enemy[0].combatant.id,
+                   spell_name="Shocking Grasp")
+    )
+    assert any(
+        "touch attack vs goblin d20=8+5=13 AC 12 -> HIT" in line
+        for line in engine._transcript
+    )
+    assert enemy[0].hp == 2
+
+
 def _inspired_ally() -> tuple[CombatEngine, CombatantState, CombatantState]:
     """Misty + one ally in 30ft, inspire courage executed on the ally."""
     misty = _combatant("misty", resources={"bardic_rounds": 12})