In-memory rule evaluator over Candidate{Item, IsFinished, ProgressPct,
CurrentSeconds, LastPlayedAt, BookmarkCount, PlayCount}. Covers all
15 fields + 7 operators + 9 sort keys including deterministic
seeded random. Personalized rules drop to false (silent) when
opts.AllowPersonalized is false. Decoupled from silo's catalog
model via the local Item struct — handler adapts.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>