Three #1953 audit follow-ups:
- perf: add migration 174 — composite index idx_kn_flats_obj_snap on
domrf_kn_flats (obj_id, snapshot_date DESC). Serves the #1956 flats_latest
CTE in best_layouts.py (DISTINCT ON (obj_id) ORDER BY obj_id, snapshot_date
DESC + self-join on (obj_id, snapshot_date)); previously only (obj_id)
existed so Postgres sorted per object. Prod: 789 569 rows, idx ~5.7 MB,
dry-run instant. Idempotent, self-wrapped BEGIN/COMMIT.
- frontend: route every max_height_m read through coerceFloat (same string-bug
class as max_far #1962). max_height_m is NUMERIC → arrives as a string on the
wire; ptica-adapt.ts read it raw at 4 sites and relied on formatInt/Math.round
coercion. Widen the type in nspd.ts and fix the stale "real number" comment in
nspd-regulation.ts.
- frontend: hide the «Дата регистрации» EGRN row entirely when
registration_date is null (~97% of parcels) instead of rendering a bare «—».
