Reconcile Notarius extraction documentation

docs/internal/stage-extract.md

@@ -4,8 +4,8 @@
 
 `extract` runs after `trim` and before `render`. It converts the canonical
 `narratio.transcript.final_trimmed` JSON into configured Notarius lane artifacts.
-An omitted or disabled Notarius section makes the stage succeed as a no-op and
-does not require a Notarius runner.
+An omitted or disabled Notarius section makes the stage explicitly self-skip
+with reason `notarius_disabled`, no outputs, and no Notarius runner.
 
 The external protocol is documented in the
 [Notarius integration contract](../integrations/notarius.md). Configuration
@@ -34,6 +34,10 @@ root, receipt, diagnostic paths, rejection/warning summaries, producing
 Narratio run ID, and invocation fingerprint. Validation completes before
 promotion, so a rejected result cannot expose a partial durable bundle.
 
+Any executed extraction outcome that replaces a different effective outcome
+marks succeeded downstream stages stale. Repeating the same disabled self-skip
+with no outputs is stable and does not repeatedly invalidate downstream stages.
+
 ## Resume Validation
 
 `internal/stage/extract_resume.go` permits a skip only when the existing stage
@@ -63,14 +67,12 @@ has passed validation and promotion.
 
 ## Implementation And Focused Tests
 
-- Stage execution and selection: `internal/stage/extract.go`,
+- Stage execution, selection, and resume validation: `internal/stage/extract.go`,
+  `internal/stage/extract_resume.go`,
   `internal/stage/extract_test.go`
-- Resume validation: `internal/stage/extract_resume.go`,
-  `internal/stage/extract_resume_test.go`
 - Subprocess boundary: `internal/adapters/notarius/subprocess.go`,
   `internal/adapters/notarius/subprocess_test.go`
 - Catalog hydration: `internal/artifacts/extraction_catalog.go`,
   `internal/artifacts/extraction_catalog_test.go`
 - Composition and downstream behavior: `internal/app/runner_test.go`,
   `internal/stage/analyze_test.go`, `internal/stage/publish_test.go`
-