fix(update): define backup_install_dir + correct gitCleanInstallBackups find

Three small bugs in the legacy git-update flow that all hung off the
same never-set variable:

1. backup_install_dir was referenced in 4 files (reset_git_backup,
   install_git_backup, use_git_backup, config_git_check) but DEFINED
   nowhere — never has been, in any branch or tag. Resolved to "", so
   "$backup_install_dir/$backupFolder" became "/backup_<ts>" (filesystem
   root, perm denied). Add it to libreportalDerivePaths beside the other
   roots, point it at $backup_dir/install (a sibling of restic's per-
   location subdirs at $backup_dir/<idx>), and add it to initFolders so
   it exists on first install.

2. gitCleanInstallBackups' find expression was
       find ... -mindepth 1 -type f ! -name '*.zip' -o -type d ! -name '*.zip' -exec rm -rf {} +
   `-o` binds looser than the implicit -a, so the -exec only applied to
   the second clause. That meant: every non-.zip DIR anywhere under the
   tree got deleted; every non-.zip FILE got matched and ignored. Even
   once $backup_install_dir resolved correctly the cleanup would've
   wrecked unrelated dirs.
   Collapsed to `-mindepth 1 -maxdepth 1 ! -name '*.zip' -exec rm -rf {} +`
   — direct children of $backup_install_dir, kill everything that isn't
   a zip, let -rf take care of the dirs. Synthetic-tree smoke test
   confirms only the .zip files survive.

3. use_git_backup.sh had a typo'd doubled var:
       copyFolders "$backup_install_dir$backup_install_dir/$backup_file_without_zip/" ...
   Reduced to the single $backup_install_dir/$backup_file_without_zip/.

All three only fire in the manual-update path (libreportal update apply
under git/local install mode); the install-blocking path is unaffected.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Signed-off-by: librelad <librelad@digitalangels.vip>

init.sh

@@ -172,6 +172,11 @@ libreportalDerivePaths() {
     install_scripts_dir="$script_dir/scripts/"
     containers_dir="$LP_CONTAINERS_DIR/"
     backup_dir="$LP_BACKUPS_DIR"
+    # Pre-update install snapshots (configs + logs zipped before the legacy
+    # git-update reset_git → checkout cycle). Distinct from restic's per-
+    # location subdirs which live at $backup_dir/<idx>. Used by
+    # gitPerformUpdate / gitCleanInstallBackups / use_git_backup / config_git_check.
+    backup_install_dir="$backup_dir/install"
 
     # Control-plane manager user (configurable; default libreportal).
     sudo_user_name="${LP_MANAGER_USER:-${sudo_user_name:-libreportal}}"
@@ -969,7 +974,7 @@ initRootHelpers()
 initFolders()
 {
 	isHeader "LibrePortal Folder Creation"
-	folders=("$docker_dir" "$containers_dir" "$ssl_dir" "$ssh_dir" "$wireguard_dir" "$logs_dir" "$configs_dir" "$backup_dir" "$restore_dir" "$migrate_dir" "$script_dir")
+	folders=("$docker_dir" "$containers_dir" "$ssl_dir" "$ssh_dir" "$wireguard_dir" "$logs_dir" "$configs_dir" "$backup_dir" "$backup_install_dir" "$restore_dir" "$migrate_dir" "$script_dir")
 	for folder in "${folders[@]}"; do
 		if [ ! -d "$folder" ]; then
 			sudo mkdir "$folder"

scripts/update/backup/install_git_backup.sh

@@ -2,7 +2,14 @@
 
 gitCleanInstallBackups()
 {
-    local result=$(runInstallOp find "$backup_install_dir" -mindepth 1 -type f ! -name '*.zip' -o -type d ! -name '*.zip' -exec rm -rf {} +)
+    # Remove the unzipped backup_<ts>/ snapshot dirs we just rolled up, keeping
+    # the .zip files themselves. `-mindepth 1 -maxdepth 1` limits to direct
+    # children of $backup_install_dir; `-exec rm -rf {} +` handles dirs via
+    # -r. The previous `-type f ! -name '*.zip' -o -type d ! -name '*.zip'`
+    # mis-applied the -exec to only the second clause (-o binds looser than
+    # the implicit -a), so it deleted every non-.zip dir under the WHOLE tree
+    # while matching no files at all.
+    local result=$(runInstallOp find "$backup_install_dir" -mindepth 1 -maxdepth 1 ! -name '*.zip' -exec rm -rf {} +)
     checkSuccess "Cleaning up install backup folders."
     local result=$(cd "$backup_install_dir" && find . -maxdepth 1 -type f -name '*.zip' | xargs ls -t | tail -n +6 | xargs -r rm)
     checkSuccess "Deleting old install backup and keeping the latest 5."

scripts/update/backup/use_git_backup.sh

@@ -12,7 +12,7 @@ gitUseExistingBackup()
 
     gitReset;
     
-    local result=$(copyFolders "$backup_install_dir$backup_install_dir/$backup_file_without_zip/" "$docker_dir" "$sudo_user_name")
+    local result=$(copyFolders "$backup_install_dir/$backup_file_without_zip/" "$docker_dir" "$sudo_user_name")
     checkSuccess "Copy the backed up folders back into the installation directory"
 
     gitCleanInstallBackups;