Complete runner lifecycle refactor

internal/app/remote_session_test.go

@@ -92,7 +92,7 @@ func TestRemoteSessionConfigIsRemovedAfterEveryCommandExit(t *testing.T) {
 		name           string
 		sessionYAML    string
 		command        []string
-		configureRun   func()
+		executor       pipelineExecutor
 		wantSuccessful bool
 	}{
 		{
@@ -126,10 +126,8 @@ inputs:
     prefix: audio/
 `,
 			command: []string{"run", "2026-05-03"},
-			configureRun: func() {
-				executeStagesFn = func(context.Context, *config.Config, BoundedPlan, RunOptions) (*RunSummary, error) {
-					return nil, errors.New("adapter failed")
-				}
+			executor: func(context.Context, *config.Config, BoundedPlan, RunOptions) (*RunSummary, error) {
+				return nil, errors.New("adapter failed")
 			},
 		},
 		{
@@ -140,10 +138,8 @@ inputs:
     prefix: audio/
 `,
 			command: []string{"run", "2026-05-03"},
-			configureRun: func() {
-				executeStagesFn = func(context.Context, *config.Config, BoundedPlan, RunOptions) (*RunSummary, error) {
-					return nil, context.Canceled
-				}
+			executor: func(context.Context, *config.Config, BoundedPlan, RunOptions) (*RunSummary, error) {
+				return nil, context.Canceled
 			},
 		},
 	}
@@ -159,16 +155,15 @@ inputs:
 
 			var downloadedPath string
 			captureRemoteSessionTempPath(t, &downloadedPath)
-			if tt.configureRun != nil {
-				origExecuteStagesFn := executeStagesFn
-				t.Cleanup(func() { executeStagesFn = origExecuteStagesFn })
-				tt.configureRun()
+			executor := tt.executor
+			if executor == nil {
+				executor = executePlan
 			}
 
 			args := append(append([]string(nil), tt.command...), "--config", pipelinePath, "--campaign-file", campaignPath)
 			var stdout bytes.Buffer
 			var stderr bytes.Buffer
-			code := Execute(args, &stdout, &stderr)
+			code := executeWithPipelineExecutor(args, &stdout, &stderr, executor)
 			if tt.wantSuccessful && code != 0 {
 				t.Fatalf("exit code = %d, want 0; stderr=%q", code, stderr.String())
 			}