fix: rewrite deletion integration tests to avoid shared-state side effects

The previous tests deleted purgatory announcements (kind 30617) and checked
for bare-repo absence via git ls-remote, which would corrupt shared-mode
test state by destroying repos other tests depend on.

New approach tests deletion of purgatory state events (kind 30618) instead:

- e-tag test: promotes a repo, creates a unique commit locally, submits a
  state event pointing to it (enters purgatory), deletes the state event by
  event ID, then verifies git push of that commit is rejected.

- a-tag coordinate test: promotes a repo, generates a fresh maintainer
  keypair, sends a replacement announcement adding that maintainer, submits
  a state event signed by the new maintainer (enters purgatory), deletes by
  coordinate 30618:<new_maintainer_pubkey>:<identifier>, then verifies git
  push is rejected.

Also extends DeletionPolicy to handle kind 30618 state events in purgatory
for both e-tag (event ID) and a-tag (coordinate) deletion paths.

0 files changed, 0 insertions, 0 deletions