Context

A Stackie plugin declares each host capability it needs in its descriptor. During initialization the host supplies a context bound to that plugin identity. Access to undeclared listeners, data, artifacts, workloads, events, contributions, or configuration is denied before any host resource is used. Absent, disabled, unentitled, or unsupported plugins are not initialized and therefore receive no capability-bearing context. Every initialization receives a fresh revocable capability lease. Shutdown, administrator disablement, and subscription loss revoke that lease before plugin code is asked to stop, so retained contexts fail closed.