copyparty doesn't try to create XDG_CONFIG_HOME during startup

[weirdrock]

Describe the bug

Quite minor, but if the XDG_CONFIG_HOME directory doesn't exist when copyparty initially starts up, it falls back to /tmp/copyparty, even if it could create the directory.
In my case, I made a fresh user account for copyparty, so there wasn't a .config directory in its home, which causes the issue

To Reproduce

Set XDG_CONFIG_HOME to a non existent directory (like ./copyparty_config)
Run copyparty
Observe it use /tmp/copyparty as a config directory

Expected behavior

Create and use ./copyparty_config as a config directory

Server details

remove the ones that are not relevant:

• server OS / version: NixOS 25.11
• what copyparty did you grab: Nix package
• how you're running it: systemd service
• run copyparty with --version and grab the last 3 lines (they start with copyparty, CPython, sqlite) and paste them below this line:
  copyparty v1.18.9 "logtail" (2025-08-01)
  CPython v3.12.10 on Linux64 [GCC 14.2.1 20250322]
  sqlite 3.48.0*1 | jinja 3.1.6 | pyftpd 1.5.10 | tftp 0.4.0