Document raw pipeline completion

docs/internal/llm.md

@@ -15,7 +15,9 @@ CompleteStructured(ctx, request, out) (response, error)
 
 The request contains prompt ID/version, profile ID, session ID, prompt input
 materials, and variables. The caller supplies a pointer target for decoded
-structured output.
+structured output. The response also carries the raw structured output bytes
+returned by the runtime so modules can preserve raw payloads in pipeline stage
+outputs.
 
 Modules that call the LLM own their prompts, schemas, prompt IDs, validators,
 and domain-specific interpretation. Provider adapters should not contain
@@ -59,6 +61,7 @@ Notarius prompt requests into Scriptorium `RunRequest` values. It:
 - lets Scriptorium render prompts, call the configured provider, and validate
   structured output;
 - unmarshals successful JSON into the caller-provided target;
+- returns the validated raw structured output bytes to the caller;
 - maps token usage and selected profile/model metadata into the Notarius
   response and manifest profile recorder.