Align internal documentation and maintained examples

docs/internal/stage-trim.md

@@ -1,16 +1,21 @@
 # Stage: trim
 
 ## Purpose
-Produce a final-trimmed transcript. By default, the stage generates bounds and applies a bounds-driven trim.
+
+Produce a final-trimmed transcript. By default, the stage generates bounds and
+applies a bounds-driven trim.
 
 ## Inputs
+
 - `transcripts/final.json`
 
 ## Outputs
+
 - `transcripts/final.trimmed.json` (or configured trim output path)
 - when trim enabled: `artifacts/session_bounds.json`
 
 ## Key Behavior
+
 When `trim.enabled=true`:
 - runs Scriptorium bounds artifact generation;
 - optionally runs render-debug output generation;
@@ -23,6 +28,16 @@ When `trim.enabled=false`:
 - copies normalized transcript to trimmed output.
 
 ## Invariants
+
 - normalized transcript is required input.
 - bounds output exists only in enabled trim path.
 - render-debug output is diagnostic and not a declared stage output.
+
+## Related Contracts And Tests
+
+- [Scriptorium](../integrations/scriptorium.md) owns bounds generation and
+  debug-render subprocess behavior.
+- [Seriatim](../integrations/seriatim.md) owns transcript trimming behavior.
+- [Configuration](../config.md#pipeline) owns trim fields and defaults.
+- Implementation and tests: `internal/stage/trim.go`,
+  `internal/stage/trim_test.go`