fix(runner): disambiguation suffix skips ids already taken by explicit combatants

tests/test_runner.py

@@ -178,6 +178,30 @@ def test_build_states_disambiguates_duplicate_ids() -> None:
     assert all(s.hp == s.combatant.hp_max for s in states)
 
 
+def test_build_states_suffix_skips_explicitly_taken_ids() -> None:
+    """A -N suffix must never land on an id another combatant already owns.
+
+    Two "gob" docs plus an explicit "gob-2" used to yield two states named
+    "gob-2" (the per-base counter ignored explicit ids), merging their
+    attrition in the engine's by-id stats keys.
+    """
+    spec = EncounterSpec(
+        map=make_map(),
+        sides=(
+            Side(
+                name="players",
+                combatants=(make_combatant("gob"), make_combatant("gob-2")),
+                zone="A",
+            ),
+            Side(name="monsters", combatants=(make_combatant("gob"),), zone="B"),
+        ),
+    )
+    states = build_states(spec)
+    ids = [s.combatant.id for s in states]
+    assert ids == ["gob", "gob-2", "gob-3"]
+    assert len(set(ids)) == 3
+
+
 def test_build_states_rejects_too_many_combatants_for_zone() -> None:
     """A zone with fewer cells than combatants is a spec error, not a runtime surprise."""
     spec = EncounterSpec(