**Related issue:** Resolves#48301
When the auto-update cron downloads a new Fleet-maintained app version,
it now carries forward the previously-active install/uninstall scripts
when they were customized (e.g. via GitOps), instead of overwriting them
with the manifest defaults. Customization is detected per-script by
comparing the active scripts against the manifest (the uninstall script
is compared against the manifest template substituted with the active
version's package IDs, since it's version-specific). When the active
scripts match the manifest, the new version's manifest scripts are used
as before.
# Checklist for submitter
- [x] Input data is properly validated, `SELECT *` is avoided, SQL
injection is prevented (using placeholders for values in statements), JS
inline code is prevented especially for url redirects, and untrusted
data interpolated into shell scripts/commands is validated against shell
metacharacters.
## Testing
- [x] Added/updated automated tests
- [x] QA'd all new/changed functionality manually