Simplify stage and Audita contracts

docs/integrations/audita.md

@@ -15,7 +15,12 @@ runner composition is documented in
 - required transcript/glossary/output/work-dir paths;
 - optional report path (required when report mode is enabled);
 - generated config and stdout/stderr log paths;
-- optional module/model/base-url/config/output-schema/concurrency settings.
+- optional per-invocation module override.
+
+The constructed runner owns static Audita settings: binary, timeout,
+credentials, default modules, model and endpoint settings, validation and output
+settings, report mode, and concurrency. The `polish` stage supplies only
+invocation-specific paths and may override modules for that invocation.
 
 ## Result Contract
 `PolishResult` returns: