Align validator identity and span domain checks

docs/internal/validators.md

@@ -23,7 +23,8 @@ Deterministic:
 - `proposal_shape`
 - `confidence_threshold`
 - `original_text_presence`
-- `non_empty_corrected_text`
+- `non_empty_resulting_segment` — rejects edits that would leave the segment
+  blank, regardless of replacement-span length.
 - `no_effect`
 - `protected_terms`
 

docs/roadmap/implementation.md

@@ -2,7 +2,7 @@
 
 **Last updated:** 2026-09-25
 
-**Status:** Ready for implementation; no stages completed.
+**Status:** In progress; Stage 1 complete.
 **Source baseline:** `a83a518` (feature roadmap); application baseline `0b6cd98`.
 **Audience:** gpt-5.6-terra coding agent.
 
@@ -192,6 +192,11 @@ Inspect remaining old-name references, retaining only deliberately historical on
 **End state:** The accurately named domain validator and application preserve the
 agreed behavior. No schema or retry workaround has been introduced.
 
+**Completed 2026-09-25.** Renamed the validator, admitted nonempty whitespace
+original spans, and verified literal spacing, blank-result protection, protected
+terms, module-policy ambiguity, and apply-time conflict attribution. The specified
+focused package tests passed.
+
 ## Stage 2 — Align Response Schema, Prompts, and LLM Validation Inputs
 
 **Work**