When the CoinGecko API fails, fall back to the last successful price
instead of 0.0, and surface a warning indicator on the price card.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
- Purchase form now includes a date picker (defaults to today)
- New Sell model, CRUD endpoints (/sells), and stats integration
- AddSell and SellList components added to dashboard
- Portfolio chart updated to reflect sells over time
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>