from_ts/to_ts are not Matrix filter fields; the server dropped them, so
the range only worked for the local encrypted-room search. Stop sending
them and post-filter server results by origin_server_ts with the same
inclusive predicate. Unit-tested; docs corrected.
Fixes#13
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA