fix(api): constrain disposition_overrides keys; close docker paper cuts

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

api/tests/test_content_resolution.py

@@ -38,3 +38,10 @@ def test_null_quest_ref_resolves():
     origin = copy.deepcopy(load_origin(DESERTER))
     origin["start_quest_id"] = None
     assert unresolved_refs(origin, world) == []
+
+
+def test_broken_disposition_npc_ref_is_detected():
+    world = load_world(CONTENT_ROOT)
+    origin = copy.deepcopy(load_origin(DESERTER))
+    origin["disposition_overrides"]["ghost_npc"] = 10
+    assert "npc:ghost_npc" in unresolved_refs(origin, world)