feat: improve agent install release layout support

- fix bare-metal Agent install config and executor path handling
- support release package layout in deploy/install.sh and release workflow
- add regression tests for Agent execution and deploy install script behavior

server/internal/installscript/deploy_install_test.go

@@ -0,0 +1,41 @@
+package installscript
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestDeployInstallScriptSyntax(t *testing.T) {
+	scriptPath := filepath.Join("..", "..", "..", "deploy", "install.sh")
+	cmd := exec.Command("sh", "-n", scriptPath)
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("install.sh syntax invalid: %v\n%s", err, output)
+	}
+}
+
+func TestDeployInstallScriptSupportsReleasePackageLayout(t *testing.T) {
+	scriptPath := filepath.Join("..", "..", "..", "deploy", "install.sh")
+	data, err := os.ReadFile(scriptPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	script := string(data)
+	for _, want := range []string{
+		`SCRIPT_DIR=$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)`,
+		`if [ -f "$SCRIPT_DIR/backupx" ] && [ -d "$SCRIPT_DIR/web" ]; then`,
+		`BIN_SOURCE="${BIN_SOURCE:-$SCRIPT_DIR/backupx}"`,
+		`WEB_SOURCE="${WEB_SOURCE:-$SCRIPT_DIR/web}"`,
+		`CONFIG_TEMPLATE="${CONFIG_TEMPLATE:-$SCRIPT_DIR/config.example.yaml}"`,
+		`发布包安装请确认当前目录包含 ./backupx、./web 和 ./install.sh。`,
+		`cat > "/etc/systemd/system/$SERVICE_NAME.service" <<UNIT`,
+		`if [ -d "/etc/nginx/conf.d" ] && [ -f "$NGINX_SOURCE" ]; then`,
+	} {
+		if !strings.Contains(script, want) {
+			t.Fatalf("install.sh missing %q", want)
+		}
+	}
+}