Plugin subscription and runtime policy

Stackie evaluates every plugin against independent package, administrator, subscription, platform, and runtime axes. Paid plugins receive no authority merely because their code is present: Stackie Cloud must issue a short-lived Ed25519-signed entitlement snapshot bound to the current account, device token, catalog version, and exact package-capability manifest.

The daemon periodically refreshes that snapshot and the persisted plugins.<id>.enabled preference. Losing either permission triggers generic reverse-dependency reconciliation: dependants stop before providers, prior capability leases are revoked, and plugin-owned persistent data remains intact.