CreateSuggestedJob ran one AnyAsync per message in the thread to decide
imported-vs-skip — an N+1 that scales with thread length. Replace it with a
single query that loads the already-imported ExternalMessageIds for the job,
then check in memory (identical skip/import behaviour), mirroring the batched
pattern RelinkThread already uses.
Build clean; backend suite 135/135 green.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
cesnimda
96b9489d49