Symptom: sold_pct_of_supply = sum_deals_24mo / supply_count_snapshot * 100
yields >100% (e.g. 199%) for fast-selling small formats due to incompatible
time windows (24-month deals vs point-in-time supply snapshot).
Option A (hotfix): clamp to 100.0, expose is_oversold=True for UI badge.
- best_layouts.py: compute sold_pct_raw, clamp with min(..., 100.0),
set is_oversold = raw > 100%
- parcel.py TopLayoutRow: add is_oversold: bool field
- best-layouts.ts TopLayoutRow: add is_oversold: boolean
- BestLayoutsBlock.tsx: show warn badge ">100%" when is_oversold=True
- tests: two new cases — raw 199% clamps + is_oversold=True;
raw 50% passes through + is_oversold=False
Closes (epic part) #271 item 5
