Fix archive block inserts failing for max-cost zkApps that emit large event/action lists (`index row size exceeds btree ... maximum` on `zkapp_events`/`zkapp_field_array`). The `UNIQUE` constraint and index over the unbounded `element_ids` arrays are dropped and content dedup is removed, so large arrays no longer overflow the btree; the dominant empty-array case is stored as `NULL` (making `events_id`/`actions_id` nullable) to avoid storage bloat, and `load_data` reconstructs `NULL` as the empty list bit-identically for the replayer. Also dedups `zkapp_commands` by transaction hash (a required companion) to avoid a `zkapp_commands_hash_key` collision once child-row ids are no longer content-stable.
