Introduce plugin/<id> installs (zip, HTTPS git, example, fork), jerapah-plugin.json manifests with jerapah semver ranges, isolated plugin dirs under data/plugins, and app version 0.1.0. Core scripts are non-editable; get-current-time moves to examples/plugins. Co-authored-by: Nasyarobby Putra <nasyarobby@gmail.com>