command_history / command_preset_history bloat and are never pruned

[pgianotto]

stats_db.py:245 stores each command twice — args (JSON) plus payload_json (the entire MQTT message). handle_command_topic (mqtt_listener.py:325) fires on every command; a multisync master publishes one message per command forwarded to each remote. Rows are commonly 200–2000 B.

These two tables are excluded from advancedStatsArchiveOldData() (api.php:929), so they grow without bound.

Suggested: add both tables to the archive/retention sweep; stop storing payload_json by default or cap its length; consider dropping the redundant args column.

Related: retention/archive gaps are filed separately.