[BUG] use `\r` line ending only on Windows when saving `stations.csv`

[j-lakeman]

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

1. press i to open station info
2. press e.g. r to rename station to reported name
3. save
4. line ending changed to Windows default

Expected behavior
keep Unix line ending

System (please complete the following information):

• OS: Ubuntu 24.04.4 LTS
• Python version: Python 3.12.3
• pipx version (if applicable): uv 0.11.19
• pipx installation method: Fully isolated
• PyRadio Version: pyradio v0.9.3.11.31
• Player used: mpv

[s-n-g]

On it...