IV Rank was stuck at 50 for all tickers because the formula returns 50.0
when iv_max == iv_min (not enough historical snapshots). Added:
- bootstrap_iv_history(): downloads 1y of closes per ticker, computes
30d rolling realized vol (annualized), saves each day to iv_history
- POST /api/options-vol/bootstrap-history endpoint (runs in background)
- OptionsLab: auto-detect when IV Rank needs bootstrapping and show
an amber banner with one-click "Initialiser historique" button
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>