feat(scenes): add deterministic romantic cinema template

src/cognitive_agent/application/scene_templates.py

@@ -33,6 +33,10 @@ _DOCUMENT_FIELDS = frozenset(
     {"id", "name", "aliases", "description", "icon", "operations", "schedule"}
 )
 
+# These templates keep their repository-backed native plan byte-for-byte and
+# only add currently authorized external-light references at request time.
+PRESERVE_BASE_EXTERNAL_LIGHT_TEMPLATE_IDS = frozenset({"romantic-cinema"})
+
 
 def normalize_scene_template_name(value: object) -> str:
     """Normalize an exact user-facing name without enabling fuzzy matching."""
@@ -289,6 +293,7 @@ class SceneTemplateRegistry:
 
 
 __all__ = [
+    "PRESERVE_BASE_EXTERNAL_LIGHT_TEMPLATE_IDS",
     "SceneTemplate",
     "SceneTemplateRegistry",
     "normalize_scene_template_name",