Implement direct Notarius extraction execution

internal/artifacts/paths.go

@@ -86,6 +86,36 @@ func SessionRunStageDirForCampaign(rootDir, campaign, sessionID, runID, stageNam
 	return filepath.Join(SessionRunRootForCampaign(rootDir, campaign, sessionID, runID), stageName)
 }
 
+// SessionRunExtractDirForCampaign returns the invocation-local extraction directory.
+func SessionRunExtractDirForCampaign(rootDir, campaign, sessionID, runID string) string {
+	return SessionRunStageDirForCampaign(rootDir, campaign, sessionID, runID, "extract")
+}
+
+// SessionRunNotariusReceiptPathForCampaign returns the invocation-local receipt path.
+func SessionRunNotariusReceiptPathForCampaign(rootDir, campaign, sessionID, runID string) string {
+	return filepath.Join(SessionRunExtractDirForCampaign(rootDir, campaign, sessionID, runID), "notarius.receipt.json")
+}
+
+// SessionRunNotariusLogPathForCampaign returns the invocation-local stderr log path.
+func SessionRunNotariusLogPathForCampaign(rootDir, campaign, sessionID, runID string) string {
+	return filepath.Join(SessionRunExtractDirForCampaign(rootDir, campaign, sessionID, runID), "notarius.stderr.log")
+}
+
+// SessionRunNotariusOutputRootForCampaign returns the invocation-local Notarius output root.
+func SessionRunNotariusOutputRootForCampaign(rootDir, campaign, sessionID, runID string) string {
+	return filepath.Join(SessionRunExtractDirForCampaign(rootDir, campaign, sessionID, runID), "notarius-output")
+}
+
+// SessionNotariusBundleDirForCampaign returns one immutable durable bundle destination.
+func SessionNotariusBundleDirForCampaign(rootDir, campaign, sessionID, runID string) string {
+	return filepath.Join(
+		SessionWorkDirForCampaign(rootDir, campaign, sessionID),
+		config.PathArtifactsDirSegment,
+		"notarius",
+		runID,
+	)
+}
+
 // SessionSpoolAudioDir returns the campaign/session/run scoped local spool audio path.
 func SessionSpoolAudioDir(spoolRoot, campaign, sessionID, runID string) string {
 	return filepath.Join(spoolRoot, campaign, sessionID, runID, config.PathAudioDirSegment)

internal/artifacts/paths_model_test.go

@@ -49,6 +49,33 @@ func TestSessionRunManifestPathForCampaign(t *testing.T) {
 	}
 }
 
+func TestSessionNotariusPathsForCampaign(t *testing.T) {
+	root := "/tmp/workspace"
+	campaign := "forsaken"
+	sessionID := "2026-04-19"
+	runID := "20260515T031522Z-a1b2c3d4"
+	extractDir := filepath.Join(root, "work", campaign, sessionID, "runs", runID, "extract")
+
+	tests := []struct {
+		name string
+		got  string
+		want string
+	}{
+		{name: "extract directory", got: SessionRunExtractDirForCampaign(root, campaign, sessionID, runID), want: extractDir},
+		{name: "receipt", got: SessionRunNotariusReceiptPathForCampaign(root, campaign, sessionID, runID), want: filepath.Join(extractDir, "notarius.receipt.json")},
+		{name: "stderr", got: SessionRunNotariusLogPathForCampaign(root, campaign, sessionID, runID), want: filepath.Join(extractDir, "notarius.stderr.log")},
+		{name: "output root", got: SessionRunNotariusOutputRootForCampaign(root, campaign, sessionID, runID), want: filepath.Join(extractDir, "notarius-output")},
+		{name: "durable bundle", got: SessionNotariusBundleDirForCampaign(root, campaign, sessionID, runID), want: filepath.Join(root, "work", campaign, sessionID, "artifacts", "notarius", runID)},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			if test.got != test.want {
+				t.Fatalf("path = %q, want %q", test.got, test.want)
+			}
+		})
+	}
+}
+
 func TestSessionPreviousPathsForCampaign(t *testing.T) {
 	root := "/tmp/workspace"
 	previousDir := SessionPreviousDirForCampaign(root, "forsaken", "2026-04-19")