Align internal documentation and maintained examples

docs/internal/stage-merge.md

@@ -1,18 +1,22 @@
 # Stage: merge
 
 ## Purpose
+
 Normalize raw transcript inputs and merge into base transcript via Seriatim.
 
 ## Inputs
+
 - `transcripts/raw/*.json`
 - `inputs/speakers.yml`
 - `inputs/autocorrect.yml`
 
 ## Outputs
+
 - `transcripts/base.json`
 - optional `artifacts/seriatim.report.json`
 
 ## Key Behavior
+
 - discovers and validates raw transcript inputs.
 - normalizes each raw transcript (`seriatim.Normalize`) into run-local scratch output.
 - merges normalized inputs (`seriatim.Run`) into base transcript.
@@ -20,6 +24,14 @@ Normalize raw transcript inputs and merge into base transcript via Seriatim.
 - materializes canonical outputs and records stage logs/generated configs.
 
 ## Invariants
+
 - merge always consumes normalized forms of raw inputs.
 - base transcript must validate before stage success.
 - report output is config-gated.
+
+## Related Contracts And Tests
+
+- [Seriatim](../integrations/seriatim.md) owns subprocess and output semantics.
+- [Configuration](../config.md#pipeline) owns operator-selected Seriatim values.
+- Implementation and tests: `internal/stage/merge.go`,
+  `internal/stage/merge_test.go`