dsh-cjbf: Backup DSH plugin and configuration to a folder

dsh-cjbf is a DSH plugin backup and recovery tool maintained by CheapGodMs. Version 1.0.0, released under the MIT license, it requires dsh >= 0.2.1-rc.5. It packages all plugins installed within a profile along with their configuration files into a timestamped folder (profile/, packages/, tool/, manifest.json, README.txt), allowing users to restore the plugin collection and configurations after switching machines. During restoration, it does not overwrite cordis.yml, leaves a rollback directory, skips link:/file: dependencies that do not exist on the new machine, and always requires explicit user confirmation on the page. The installation command is `dsh plugin --profile <profile> add dsh-cjbf`; it also provides a `plugin_backup` agent tool that covers the status, scan, backup, and find actions.