Add Seriatim trim adapter support

internal/adapters/seriatim/runner.go

@@ -1,4 +1,4 @@
-// Package seriatim declares the adapter contract for transcript merge execution.
+// Package seriatim declares the adapter contract for transcript merge/trim execution.
 package seriatim
 
 import (
@@ -8,9 +8,10 @@ import (
 
 // TODO: implement a real Seriatim subprocess adapter.
 
-// Runner is the adapter boundary for seriatim merge invocations.
+// Runner is the adapter boundary for seriatim merge/trim invocations.
 type Runner interface {
 	Run(ctx context.Context, req MergeRequest) (MergeResult, error)
+	Trim(ctx context.Context, req TrimRequest) (TrimResult, error)
 }
 
 // MergeRequest describes a seriatim merge invocation.
@@ -38,3 +39,28 @@ type MergeResult struct {
 	OutputSchema         string
 	Metadata             map[string]any
 }
+
+// TrimRequest describes a seriatim trim invocation.
+type TrimRequest struct {
+	Binary              string
+	InputTranscriptPath string
+	OutputTrimmedPath   string
+	KeepSelector        string
+	StdoutLogPath       string
+	StderrLogPath       string
+	GeneratedConfigPath string
+	Timeout             time.Duration
+}
+
+// TrimResult describes a trim output.
+type TrimResult struct {
+	OutputTrimmedPath   string
+	StdoutLogPath       string
+	StderrLogPath       string
+	GeneratedConfigPath string
+	ExitCode            int
+	Duration            time.Duration
+	InvokedBinary       string
+	KeepSelector        string
+	Metadata            map[string]any
+}