The Copy button in the Open WebUI interface silently failed on
GNOME/Wayland/Flatpak because the webview session permission handlers
did not include 'clipboard-sanitized-write'. Electron denied the
navigator.clipboard.writeText() call, but the web app saw no error
and briefly showed 'Copied' without actually writing to the clipboard.
Added 'clipboard-sanitized-write' to both permission handler whitelists:
- Per-connection content window handler
- session-created handler for webview partition sessions
The API key is now saved in config.json and reused on subsequent
startups instead of being regenerated every time, which was breaking
existing integrations that relied on a stable key.
Closes#102
