The install script overwrote the correct appsettings.json shipped in the
release archive with a hardcoded copy that was missing newer required
fields (ApiKey, ProxyPort, EnableChangedTitleCache) and had structural
differences (Lidarr/Readarr as arrays instead of objects), causing the
service to fail on startup.
- Remove hardcoded appsettings.json from install script (release archive
already ships the correct version)
- Backup and restore appsettings.json during updates to preserve user
configuration
Closes#11665
