Extract caption text policy

docs/prompt-architecture-improvement-plan.md

@@ -443,6 +443,10 @@ Already isolated:
   `CaptionMetadataRouteRequest`, `CaptionMetadataRouteDependencies`, and
   `CaptionMetadataRoute`; `caption_naturalizer.py` keeps compatibility wrappers,
   profile handling, trigger behavior, and text fallback.
+- `caption_text_policy.py` owns caption sentence helpers, trigger wrapping,
+  formatter-hint append, row-value fallback wrappers, cast text wrappers,
+  single-caption front parsing, route dependency assembly, and caption metadata
+  helper callbacks used by `caption_metadata_routes.py`.
 - metadata-family action labels from `action_family` and `position_family` via
   `caption_policy.py`.
 - shared row route metadata reads from `route_metadata.py`.