Validate item template formatter hints

docs/prompt-architecture-improvement-plan.md

@@ -337,15 +337,14 @@ Keep here:
 - direct category-specific wording.
 - optional object-style item templates with route metadata such as
   `action_family`, `action_type`, `position_family`, `family`, `position_key`,
-  and `position_keys`; string templates remain valid and fall back to Python
-  inference.
+  `position_keys`, and `formatter_hint`; string templates remain valid and fall
+  back to Python inference.
 
 Improve later:
 
-- add `formatter_hint` fields only where needed, not globally;
 - keep `tools/prompt_map_audit.py` passing; it now checks referenced
-  expression/composition/scene pools and item-template axes for both string and
-  object templates.
+  expression/composition/scene pools, item-template axes, and object-template
+  metadata values for both string and object templates.
 
 ### Node / UI Path