Bulk Delete Logs

Request body for POST /logs/bulk-delete.

PR 26 adds subject + ids, matching the shape the other bulk routes use. The three per-channel lists stay accepted for one deploy so a client on the previous bundle keeps working; PR 50 drops them.

PR 44 adds selection — "delete everything matching this filter" — which the other bulk routes express through TargetedBulkRequest. This one cannot inherit it while the three deprecated per-channel lists survive, so it restates the field and defers the resolution to the same resolve_selection. PR 50 drops the legacy lists and this becomes a TargetedBulkRequest like its four siblings.

Response for POST /logs/bulk-delete.