Re-scan the plugins directory and report the reconciled dynamic-library inventory (the sibling of config/reload). A store change takes effect on the next store (re)load

The result of re-scanning the plugins directory (POST /api/v1/admin/plugins/reload): the current dynamic-library inventory, each with its ABI-validity. Reconciles the reported set to the folder (the folder is the source of truth), exactly as config/reload reconciles config to disk. A store change still applies on the next store (re)load, not as a hot swap.