ui: add search_chats tool (#32051)
* ui: add search_chats tool
* add from_timestamp / to_timestamp
* ui: search_chats review fixes
- keep search_chats disabled on import, copy tool policy on fork
- stream messages without attachment payloads, one transaction for time ranges
- keep the output within budget, cut whole messages from the older end
- reject impossible date-times, quote titles and attachment names
- typed readOnly tables, move localIsoString to formatters as formatLocalIso
Assisted-by: Claude (Opus 5.5 Medium)
---------
Co-authored-by: Aleksander Grygier <aleksander.grygier@gmail.com>
