refactor(ct): migrate manual update backups to create_backup (batch 1)

Replace ad-hoc mv/cp .bak patterns with create_backup/restore_backup across
58 update scripts so failed updates can roll back via the shared ERR trap.

Co-authored-by: Cursor <cursoragent@cursor.com>

ct/termix.sh

@@ -143,12 +143,10 @@ EOF
     fi
     msg_ok "Migrated Configuration"
 
-    msg_info "Backing up Data"
-    cp -r /opt/termix/data /opt/termix_data_backup
-    cp -r /opt/termix/uploads /opt/termix_uploads_backup
-    msg_ok "Backed up Data"
+    create_backup /opt/termix/data /opt/termix/uploads
 
     CLEAN_INSTALL=1 fetch_and_deploy_gh_release "termix" "Termix-SSH/Termix" "tarball"
+    restore_backup
 
     msg_info "Recreating Directories"
     mkdir -p /opt/termix/html \
@@ -177,11 +175,6 @@ EOF
     $STD npm cache clean --force
     msg_ok "Set up Production Dependencies"
 
-    msg_info "Restoring Data"
-    cp -r /opt/termix_data_backup /opt/termix/data
-    cp -r /opt/termix_uploads_backup /opt/termix/uploads
-    rm -rf /opt/termix_data_backup /opt/termix_uploads_backup
-    msg_ok "Restored Data"
 
     msg_info "Updating Frontend Files"
     rm -rf /opt/termix/html/*