demand_index used a fixed clamp01(velocity/50); on a live prod refresh
all 8 ЕКБ districts sold ≥50/mo so it saturated to 1.0 everywhere — zero
discrimination between districts. Redesign to mirror infra_index:
normalize each district's unit_velocity against the city reference (MAX
district velocity per refresh run), so demand always discriminates and
self-calibrates as the market grows (no magic constant to rot).
- normalize_demand(velocity, *, city_reference_velocity), pure + graceful
(None stays None; reference<=0 -> honest 0.0, no ZeroDivisionError)
- refresh_locations now two-pass: collect velocities (one
compute_market_metrics per district, no O(n^2)), derive city reference,
normalize + upsert; SAVEPOINT-per-row and counters preserved
- remove _DEMAND_SATURATION_UPM constant; log city_reference_velocity
- tests: rewrite demand normalization + add end-to-end city-relative
suite incl. discrimination regression guarding the all-1.0 prod bug
Refs #948
Promote district to a first-class `location` entity (ТЗ §8.2), ADDITIVE — no
district->FK refactor. New `location` table keyed by district_name (joinable by
string), carrying 4 normalized [0,1] indices (NULL when no data, never 0):
- infra: _district_poi_score / _city_avg_poi_score (per-district POI aggregate)
- competition: market_metrics.overstock_index (available/stuck competing supply
— orthogonal to demand; NOT sell-through, which is market-heat correlated w/ demand)
- demand: market_metrics.unit_velocity (saturating /50)
- future_supply: future_supply_pressure.index (passthrough, already 0..1)
- data/sql/146_location.sql: idempotent table + UNIQUE(district_name) + range
CHECK + centroid GIST
- services/site_finder/locations.py: compute_location_indices (reuses forecast
per-district fns) + refresh_locations (SAVEPOINT per-row, CAST, ON CONFLICT)
- workers/tasks/location_refresh.py + beat (Mon 07:00 MSK, after supply-layers)
- api/v1/locations.py: read-only GET list + GET by name (analyst+admin via rbac,
frontend pilot-gated)
- tests: 34 (normalization 0..1/null, competition⊥demand orthogonality, idempotent
upsert, read API list/by-name/404)
Part of #948 (Part A insight shipped #1164).
