Implements QQQ core's RecordSearchProviderInterface so the Next UI global
search (POST /qqq/v1/search) is served from the Quick Search index for the
tables this QBit indexes. The provider returns record ids only; core re-reads
them through QueryAction, so table permissions, record security locks and
labels stay core's job. One bounded _msearch per call, with a short backoff
after a failure during which core falls back to its own LIKE search.
Builds against the released QQQ 4.1.0-RC.2, the first release that carries
the SPI (replaces the 4.1.0-SNAPSHOT pin from PR #32).
Re-signed from PR #32 (originally 75dc2b3).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>