PR #509 removed CAST(:target_year AS integer) and CAST(:target_house_type AS text)
from the IS NOT NULL predicates in _fetch_analogs, citing audit finding #9 (perf).
This broke production: psycopg3 prepared statement could not determine $4 type
when target_house_type=None, raising AmbiguousParameter at plan time. The CAST
in the THEN branch is not enough — PG planner needs the type to evaluate
IS NOT NULL itself.
The inline comment at lines 814-816 explicitly documented this requirement;
PR #509 misread the audit finding. Per-row CAST cost on ≤300 rows is negligible
vs production breakage. Restoring CAST forms; THEN-branch CASTs untouched
(they were never removed).
Verified prod stack trace 2026-05-24 ~12:25 (target_year=1978, target_house_type=None).
