Fixes playtime sync for lua apps. Previously, playtime was not being read from localconfig.vdf reliably due to two bugs and one incorrectly handled behavior:
- The VDF parser path was missing the root section key, so it never found the app's playtime entry for certain types of games (AutoCloud)
- The VDF file sometimes couldn't be opened on game exit because Steam had it locked (switched to shared-access read)
- A very dumb logic issue (that was entirely my fault) could cause the playtime data to be kept local.
This release also includes other minor bug fixes (error handling, resource cleanup, thread safety stuff).
Thanks to Valekatoz for patiently testing as I tried to work out this issue.