Periodic deletion of consent records older than retention_days.

Opt-in: the package does not start this GenServer on its own. Add it to your host application's supervision tree:

children = [
  MyApp.Repo,
  # ... other children ...
  {Keksdose.Retention, retention_days: 395}
]

Or via config + Application:

# config/config.exs
config :keksdose,
  repo: MyApp.Repo,
  retention_days: 395,
  retention_check_interval_ms: :timer.hours(24)

# MyApp.Application
children = [MyApp.Repo, Keksdose.Retention]

Setting retention_days: nil (or omitting the config) disables purging; the GenServer starts but never deletes. Useful if you want the process in your tree before deciding on a retention policy.

Emits [:keksdose, :retention, :purged] on every successful run (including zero-deletion runs).

Performance note

Purges run as a single DELETE WHERE inserted_at < cutoff. On tables with millions of rows-to-delete (e.g. enabling retention for the first time after years of accumulation) the initial run may briefly lock the table and bloat WAL on PostgreSQL. For that scenario, do a manual batched cleanup with DELETE ... LIMIT 10_000 before relying on the GenServer for steady-state housekeeping.