Replace structured LLM dependency with Audita adapter

docs/architecture.md

@@ -21,7 +21,7 @@ Implemented today:
 - Runtime validator models and deterministic validators.
 - Deterministic validator-chain execution in the runner with cardinality enforcement.
 - Module-level validator decision/rejection reporting.
-- Internal structured LLM client contract plus an `instructor-go`-backed adapter package.
+- Internal structured LLM client contract plus an Audita-owned OpenAI-compatible structured LLM adapter package.
 - Bounded FIFO LLM scheduler infrastructure with context-aware permit handling.
 - Runtime primary/validation LLM effective-config resolution helpers with validation inheritance.
 - Generic JSON prompt/response diagnostics writer primitives with secret redaction.
@@ -133,7 +133,7 @@ internal/framework/validators/
   llm_validators.go
 
 internal/framework/llm/
-  instructor_client.go
+  openai_compatible_client.go
   scheduler.go
   effective_config.go
   diagnostics.go
@@ -233,14 +233,33 @@ Current caveat:
 `internal/framework/contracts` now defines a typed structured-completion contract:
 - `StructuredLLMClient.CompleteStructured(ctx, req, out)`
 - caller-owned typed decode target via `out` pointer.
+- caller-selected structured response schema metadata via `StructuredCompletionRequest.ResponseSchema`.
 
-`internal/framework/llm` provides `InstructorClient`, an internal adapter over `github.com/jxnl/instructor-go`:
-- configurable `base_url`, model, optional API key, retries, mode, HTTP client, and request timeout;
+`internal/framework/llm` provides `OpenAICompatibleClient`, a direct `net/http` adapter over OpenAI-compatible chat completions:
+- configurable `base_url`, model, optional API key, retries, HTTP client, and request timeout;
 - OpenAI-compatible endpoint behavior (for example OpenAI/OpenRouter/local-compatible base URLs);
-- default mode is JSON mode (`ModeJSON`), with optional tool-call mode (`ModeToolCall`);
 - request message translation from `contracts.LLMMessage` to chat-completions messages;
+- strict `response_format.type = json_schema` with registered structured response schemas (`strict: true`, schema name, and schema body);
 - response metadata mapping (provider/model/token usage) into Audita-owned response types;
-- API-key redaction in adapter-returned errors.
+- API-key redaction in adapter-returned errors;
+- context cancellation and timeout propagation through request contexts and HTTP client timeouts;
+- bounded retry behavior for transient request failures and malformed retryable structured responses.
+
+Structured response schemas are owned by Audita in `internal/framework/responseschema` and currently include:
+- key `correction_set`:
+  - id `audita.correction_set`
+  - version `v1`
+  - name `audita_correction_set_v1`
+  - sha256 `05f8ff3fa04f68115c0cb1859d2656f51aa5c0bae8ff2470b2d4f6f531953195`
+- key `validator_decision_set`:
+  - id `audita.validator_decision_set`
+  - version `v1`
+  - name `audita_validator_decision_set_v1`
+  - sha256 `b73f4790b98fbb955f0aec5496dd8ce9a8fe14aa2f35c700b4b4e5634f106fd5`
+
+Provider-level structured output is treated as a guardrail, not a trust boundary:
+- the adapter decodes assistant message content into caller-owned structs;
+- proposal-generation and validator layers continue local validation (shape, cardinality, confidence bounds, and proposal-index semantics) before changes can be applied.
 
 Current runtime boundary:
 - the default CLI runtime path (without explicit module selection) instantiates the full production module sequence.
@@ -252,6 +271,14 @@ Current runtime boundary:
 - primary/validation effective-config resolution helpers, including validation inheritance fallback to total LLM concurrency settings;
 - generic interaction diagnostics primitives that write machine-readable JSON artifacts for request metadata, request payload, response payload, and optional error payload with secret redaction.
 
+Structured LLM diagnostics behavior:
+- proposal-generation and validator diagnostics include structured response schema metadata (`id`, `version`, `name`, `sha256`) when schema-driven calls are made;
+- API keys and bearer tokens are redacted from request/response/error diagnostics artifacts and surfaced errors.
+
+Dependency posture:
+- the runtime no longer depends on `instructor-go`;
+- structured LLM behavior is implemented through Audita-owned code paths behind `StructuredLLMClient`.
+
 LLM concurrency runtime behavior:
 - `total` concurrency bounds all proposal and validation LLM calls.
 - `proposal` concurrency adds a proposal-only sub-cap, composed with total.