Finish Scriptorium runtime documentation

docs/internal/llm.md

@@ -21,13 +21,18 @@ Modules that call the LLM own their prompts, schemas, prompt IDs, validators,
 and domain-specific interpretation. Provider adapters should not contain
 domain-specific prompt logic.
 
+Prompt input materials carry source or reference bytes with optional origin
+metadata. The Scriptorium-backed runtime receives them as named artifacts rather
+than rendered prompt strings owned by Notarius modules.
+
 ## Production Client Construction
 
 `internal/cli` builds the production LLM client from the effective config:
 
 1. collect production Scriptorium prompt and schema assets from module packages;
 2. create a Scriptorium-backed structured client using effective Scriptorium
-   profile source settings;
+   profile source settings from `scriptorium.profile_dir` or
+   `scriptorium.profile_file`;
 3. create a scheduler from global LLM concurrency;
 4. wrap the client with `NewScheduledClient`;
 5. let the runtime report non-secret profile manifest metadata after calls.
@@ -42,8 +47,10 @@ profile ID before pipeline execution.
 Notarius prompt requests into Scriptorium `RunRequest` values. It:
 
 - validates the caller output target and prompt ID;
-- converts `LLMInputMaterial` values into inline Scriptorium artifacts;
-- passes `session_id` through Scriptorium variables when present;
+- converts `LLMInputMaterial` values into inline Scriptorium artifacts, using a
+  single space for empty material so optional blank references remain explicit;
+- passes `session_id` through Scriptorium variables and request metadata when
+  present;
 - sends explicit profile IDs only when the request supplies one;
 - lets Scriptorium render prompts, call the configured provider, and validate
   structured output;
@@ -53,7 +60,9 @@ Notarius prompt requests into Scriptorium `RunRequest` values. It:
 
 Generated-output validation failures are returned as Notarius errors. Provider
 and runtime errors are wrapped with prompt context and bearer tokens are
-redacted from error strings.
+redacted from error strings. Prompt text, raw source input, reference content,
+schema JSON, API keys, and bearer tokens are not added to default diagnostics or
+run manifests.
 
 ## Scheduler