Add gpx type, fix file replacement

CHDataManagement/Model/FileResource.swift

@@ -108,7 +108,11 @@ final class FileResource: Item, LocalizedItem {
     }
 
     func save(textContent: String) -> Bool {
-        content.storage.save(fileContent: textContent, for: id)
+        guard content.storage.save(fileContent: textContent, for: id) else {
+            return false
+        }
+        modifiedDate = .now
+        return true
     }
 
     func dataContent() -> Foundation.Data? {

CHDataManagement/Model/FileType.swift

@@ -90,6 +90,8 @@ enum FileType: String {
 
     case txt
 
+    case gpx
+
     // MARK: Model
 
     case stl
@@ -164,7 +166,7 @@ enum FileType: String {
             return .video
         case .mp3, .aac, .m4b, .m4a:
             return .audio
-        case .json, .conf, .yaml, .txt:
+        case .json, .conf, .yaml, .txt, .gpx:
             return .text
         case .html, .cpp, .swift, .sh, .js, .css:
             return .code