9 docs + index in docs-src/architecture/ documenting the deterministic
retrieval engine: retrieval pipeline, authority rerank, source_class,
source_role, control-intent + diversity, assessment, confidence,
explainability + supersede, framework_* layer. Each doc carries the exact
constants, the rationale behind them, code refs, and the failure class
it addresses. Audit/onboarding reference.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>