The via_search / shorts_probed partials used `WHERE via_search` / `WHERE NOT
shorts_probed`, but the queries filter with `.is_(True)`/`.is_(False)` (SQL
`IS TRUE`/`IS FALSE`), which Postgres's partial-index prover does NOT match to a
bare-boolean predicate — so both fell back to a full seq scan (the shorts-probe
job kept full-scanning for its work queue, the exact thing PERF-3 meant to fix).
Align the predicates to the query form: `WHERE via_search IS TRUE` and
`WHERE shorts_probed IS FALSE`. Verified on the prod-sized localdev: both now
Index Only Scan (via_search 44,683 -> 3 buffers; shorts_probed 44,683 -> 1).
Gate green (346 pytest).
peter
94dbe4b228