fix: второй стабилизационный pass vault layout — sync payload, bindings, vaultPath, tests

sync_apply.go:
- applyRemoteNodeCreate: полный payload (template_id/fs_path/sort_order/archived),
  INSERT сохраняет все поля, для folder-like создаётся физическая папка.
- applyRemoteNodeUpdate: принимает fs_path/template_id/archived,
  физическое переименование папки при изменении title/fs_path.
- applyRemoteNodeMove: принимает fs_path, обновляет parent_id+fs_path,
  физически перемещает папку (folder-like) или file record (note/file).

bindings_nodes.go:
- MoveNode: node.FsPath = newFsPath после UpdateFsPath;
  sync.RecordOp отправляет новый fs_path; note/file move to root — файл в vault root.
- RenameNode: EntityFile для file, EntityNote для note;
  коллизия → генерация уникального имени; файл переименовывается только после os.Rename.
- DeleteNode: единый вызов a.files.DeleteNodeAndChildren(), дублирование удалено.
- Исправлен deadlock с SetMaxOpenConns(1) — Query/Exec больше не конфликтуют.

files.Service.vaultPath: filepath.Rel-based проверка,
  sibling-prefix escape (/tmp/vault vs /tmp/vault_evil) отклоняется.

VaultCheck: SQL JOIN с n.deleted_at IS NULL, чтобы удалённые узлы
  не показывались как missing files.

Добавлены тесты: RenameFileNodeUsesEntityFile, MoveNoteToRoot,
  DeleteFolderLeavesVaultCheckHealthy, SyncNodeCreatePreservesFields,
  VaultPathSiblingPrefixEscape.

internal/core/files/file.go

@@ -102,12 +102,24 @@ func validateName(name string) error {
 
 // vaultPath resolves a relative vault path and checks it stays within jail.
 func (s *Service) vaultPath(rel string) (string, error) {
-	abs := filepath.Join(s.vaultRoot, rel)
-	cleaned := filepath.Clean(abs)
-	if !strings.HasPrefix(cleaned, filepath.Clean(s.vaultRoot)) {
-		return "", fmt.Errorf("path escapes vault root")
+	if rel == "" {
+		return "", fmt.Errorf("empty path")
 	}
-	return cleaned, nil
+	if filepath.IsAbs(rel) {
+		return "", fmt.Errorf("absolute path not allowed: %s", rel)
+	}
+	cleaned := filepath.Clean(rel)
+	joined := filepath.Join(s.vaultRoot, cleaned)
+	joinedClean := filepath.Clean(joined)
+
+	relToVault, err := filepath.Rel(s.vaultRoot, joinedClean)
+	if err != nil {
+		return "", fmt.Errorf("path escapes vault root: %s", rel)
+	}
+	if relToVault == ".." || strings.HasPrefix(relToVault, ".."+string(filepath.Separator)) {
+		return "", fmt.Errorf("path escapes vault root: %s", rel)
+	}
+	return joinedClean, nil
 }
 
 // absPathSafe resolves an absolute path and checks jail if it's under vault.
@@ -447,11 +459,13 @@ func (s *Service) DeleteNodeAndChildren(nodeID string) error {
 		}
 	}
 	_ = s.deleteFileRecords(nodeID)
-	// Move physical folder to trash if the node has fs_path
 	n, err := s.nodes.GetActive(nodeID)
 	if err == nil && n.FsPath != "" {
-		src := filepath.Join(s.vaultRoot, n.FsPath)
-		if info, err := os.Stat(src); err == nil && info.IsDir() {
+		src, vaultErr := s.vaultPath(n.FsPath)
+		if vaultErr != nil {
+			src = filepath.Join(s.vaultRoot, n.FsPath)
+		}
+		if info, statErr := os.Stat(src); statErr == nil && info.IsDir() {
 			trashDir := filepath.Join(s.vaultRoot, ".verstak", "trash")
 			os.MkdirAll(trashDir, 0o750)
 			trashPath := filepath.Join(trashDir, n.ID+"_"+templates.SafeDisplayNameToPathSegment(n.Title))

internal/core/files/file_test.go

@@ -305,6 +305,42 @@ func TestPreviewImportDir(t *testing.T) {
 	}
 }
 
+func TestVaultPathSiblingPrefixEscape(t *testing.T) {
+	vaultRoot := "/tmp/vault"
+	svc := &Service{vaultRoot: vaultRoot}
+
+	// Normal path should pass
+	_, err := svc.vaultPath("some/file.txt")
+	if err != nil {
+		t.Fatalf("expected OK, got: %v", err)
+	}
+
+	// Sibling-prefix escape should fail
+	// vault=/tmp/vault, path goes to /tmp/vault_evil -> should be rejected
+	_, err = svc.vaultPath("../vault_evil/file.txt")
+	if err == nil {
+		t.Error("expected error for sibling-prefix escape, got nil")
+	}
+
+	// Direct escape with ../..
+	_, err = svc.vaultPath("../../etc/passwd")
+	if err == nil {
+		t.Error("expected error for path escape, got nil")
+	}
+
+	// Absolute path
+	_, err = svc.vaultPath("/etc/passwd")
+	if err == nil {
+		t.Error("expected error for absolute path, got nil")
+	}
+
+	// Empty path
+	_, err = svc.vaultPath("")
+	if err == nil {
+		t.Error("expected error for empty path, got nil")
+	}
+}
+
 func TestGuessMIME(t *testing.T) {
 	cases := map[string]string{
 		"a.md":      "text/plain",