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/agent/executor_test.go

@@ -0,0 +1,34 @@
+package agent
+
+import (
+	"reflect"
+	"testing"
+	"time"
+)
+
+func TestBuildBackupTaskSpecParsesJSONSourcePaths(t *testing.T) {
+	spec := &TaskSpec{
+		TaskID:          7,
+		Name:            "root-files",
+		Type:            "file",
+		SourcePaths:     `["/root","/etc"]`,
+		ExcludePatterns: `["*.log","tmp"]`,
+	}
+
+	got := buildBackupTaskSpec(spec, time.Unix(0, 0), "/var/lib/backupx-agent/tmp")
+
+	if !reflect.DeepEqual(got.SourcePaths, []string{"/root", "/etc"}) {
+		t.Fatalf("source paths = %#v", got.SourcePaths)
+	}
+	if !reflect.DeepEqual(got.ExcludePatterns, []string{"*.log", "tmp"}) {
+		t.Fatalf("exclude patterns = %#v", got.ExcludePatterns)
+	}
+}
+
+func TestParseStringListFieldKeepsLegacyLineFormat(t *testing.T) {
+	got := parseStringListField("/root\n /etc \n")
+	want := []string{"/root", "/etc"}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("paths = %#v, want %#v", got, want)
+	}
+}