Finish prototype for web interface

Only unlock unlockable songs at first write

GC-local-server-rewrite/common/IOptionServiceResponse.cs

@@ -0,0 +1,14 @@
+namespace GCLocalServerRewrite.common;
+
+public interface IOptionServiceResponse
+{
+    string FileName { get; }
+    
+    long NotBeforeUnixTime { get; }
+    
+    long NotAfterUnixTime { get; }
+    
+    string Md5 { get; }
+
+    int Index { get; }
+}