fix(models): reject combatant ids that misparse the transcript format

tests/test_models.py

@@ -189,6 +189,22 @@ class TestCombatant:
         with pytest.raises(ValidationError):
             Combatant.model_validate(_combatant_dict(hit_dice="1d8"))
 
+    @pytest.mark.parametrize("bad_id", ["a: b", " goblin", "goblin ", ""])
+    def test_rejects_transcript_hostile_id(self, bad_id: str) -> None:
+        # Given an id that would misparse the "round N id: message" transcript
+        # (contains ": ") or is empty / padded with whitespace
+        # When/Then validation rejects it
+        with pytest.raises(ValidationError):
+            Combatant.model_validate(_combatant_dict(id=bad_id))
+
+    def test_accepts_id_with_colon_without_space(self) -> None:
+        # Given an id using ":" as a separator but never ": " (weapon-style
+        # ids are safe for the transcript parser)
+        # When validated
+        combatant = Combatant.model_validate(_combatant_dict(id="goblin:claw"))
+        # Then it is accepted
+        assert combatant.id == "goblin:claw"
+
     def test_frozen(self) -> None:
         # Given a validated combatant
         combatant = Combatant.model_validate(_combatant_dict())