automatically delete a feed that reaches max trigger count

once a feed has exhausted its triggers, should be deleted for convenience?
it might also be nice to infer which triggers are one offs as well and delete them regardless of max trigger since they will not fire again.

No files, tests, or entry points are identified in the issue. First clarify whether max-trigger and one-off feeds should be deleted, then locate the feed lifecycle implementation and add tests proving deletion occurs only under the agreed conditions.

Written by the indexing model from the issue text.