Refactor validators into built-in registry chains

docs/architecture.md

@@ -132,6 +132,10 @@ internal/framework/validators/
   llm_batching.go
   llm_validators.go
 
+internal/validators/
+  registry.go
+  chains.go
+
 internal/framework/llm/
   openai_compatible_client.go
   scheduler.go
@@ -428,6 +432,63 @@ These primitives are wired into the production runner and report model. The gram
 
 Validator rejections are reported distinctly from proposal-application skips.
 
+Validator composition is now explicit and registry-backed through `internal/validators`:
+- built-in validator registry with stable keys and lookup/build failure for unknown keys;
+- built-in chain definitions per production module key;
+- production modules resolve validator chains from those built-in definitions.
+
+Stable built-in validator keys:
+- deterministic:
+  - `confidence_threshold`
+  - `original_text_presence`
+  - `non_empty_corrected_text`
+  - `no_effect`
+  - `protected_terms`
+- LLM-backed:
+  - `spoken_form_plausibility`
+  - `meaning_reversal_review`
+  - `editorial_review`
+  - `grammar_review`
+  - `spoken_word_review`
+
+Built-in module chains:
+- `glossary`:
+  - `no_effect`
+  - `original_text_presence`
+  - `confidence_threshold`
+  - `protected_terms`
+  - `non_empty_corrected_text`
+  - `spoken_form_plausibility`
+  - `meaning_reversal_review`
+- `homophones`:
+  - `no_effect`
+  - `original_text_presence`
+  - `confidence_threshold`
+  - `protected_terms`
+  - `non_empty_corrected_text`
+  - `spoken_form_plausibility`
+  - `meaning_reversal_review`
+- `spoken_word`:
+  - `no_effect`
+  - `original_text_presence`
+  - `confidence_threshold`
+  - `protected_terms`
+  - `non_empty_corrected_text`
+  - `spoken_word_review`
+  - `meaning_reversal_review`
+- `grammar`:
+  - `no_effect`
+  - `original_text_presence`
+  - `confidence_threshold`
+  - `protected_terms`
+  - `non_empty_corrected_text`
+  - `grammar_review`
+  - `meaning_reversal_review`
+
+1.0 boundary:
+- validator chains are built-in and not user-configurable from config/CLI.
+- existing threshold and batching knobs remain configurable.
+
 ## Implemented LLM-backed validator infrastructure
 `internal/framework/validators` now includes LLM-backed validator support:
 - typed request/response models for structured LLM validation;
@@ -563,6 +624,7 @@ Current process reports also include:
 - run-level module summary totals and failed module instance metadata.
 - module-level validator decisions and validator rejections.
 - optional decision-level diagnostic artifact paths for validator LLM interactions when available.
+- stable validator keys in `validator_name` fields for validator decisions/rejections.
 - explicit report metadata:
   - report schema name;
   - report schema version;