Protect transcript refinement resume semantics

docs/internal/stage-render.md

@@ -26,7 +26,8 @@ records that may consume rendered transcripts.
 - records input provenance, output paths, adapter metadata, logs, and generated config refs.
 - when `pipeline.render.enabled=false`, completes successfully with no outputs
   and records explanatory metadata. This is not an explicit self-skip: both
-  manifests record success, and enabling render later requires a forced run.
+  manifests record success. Because enablement is fingerprinted, enabling
+  render later automatically makes the prior result non-resumable.
 
 ## Failure Semantics
 
@@ -40,9 +41,20 @@ records that may consume rendered transcripts.
 - only `format: markdown` is supported.
 - render stage owns production of built-in Markdown transcript sources.
 
+## Resume Semantics
+
+The versioned semantic fingerprint covers enablement, final format, resolved
+title (including the session-title fallback), timestamp, segment-ID and
+metadata inclusion, both canonical input identities, and both Markdown output
+identities. Seriatim's executable, timeout, and report behavior are operational
+and do not invalidate rendered transcripts. A render-only change leaves the
+independent `extract` sibling reusable while invalidating their shared
+downstream consumers.
+
 ## Related Contracts And Tests
 
 - [Seriatim](../integrations/seriatim.md) owns render subprocess behavior.
 - [Configuration](../config.md#pipeline) owns render fields and defaults.
 - Implementation and tests: `internal/stage/render.go`,
-  `internal/stage/render_test.go`
+  `internal/stage/render_test.go`,
+  `internal/stage/semantic_contracts_refinement.go`