Implement Seriatim subprocess adapter

internal/adapters/seriatim/runner.go

@@ -1,7 +1,10 @@
 // Package seriatim declares the adapter contract for transcript merge execution.
 package seriatim
 
-import "context"
+import (
+	"context"
+	"time"
+)
 
 // TODO: implement a real Seriatim subprocess adapter.
 
@@ -15,6 +18,9 @@ type MergeRequest struct {
 	GeneratedConfigPath        string
 	InputTranscriptPaths       []string
 	OutputMergedTranscriptPath string
+	ReportPath                 string
+	SpeakersPath               string
+	AutocorrectPath            string
 	StdoutLogPath              string
 	StderrLogPath              string
 }
@@ -22,5 +28,13 @@ type MergeRequest struct {
 // MergeResult describes a merge output.
 type MergeResult struct {
 	MergedTranscriptPath string
+	ReportPath           string
+	StdoutLogPath        string
+	StderrLogPath        string
+	GeneratedConfigPath  string
+	ExitCode             int
+	Duration             time.Duration
+	InvokedBinary        string
+	OutputSchema         string
 	Metadata             map[string]any
 }