Add advanced calendar features and toast notifications

Features:
- Toast notifications system (replaces alerts/confirms)
- Shift+click range selection for blocking dates
- Ctrl/Cmd+click for non-contiguous multi-date selection
- Progress indicators for all async operations
- Improved blocked dates list with formatted dates
- Red styling for blocked dates in calendar
- Blue styling for pending dates (Ctrl+click)
- Weekly schedule awareness (confirm before blocking work days)
- Non-working day styling (gray, dashed border)

Other improvements:
- Featured flag for menus (DB migration script included)
- Image handling fixes (renamed PNG files, updated references)
- Optimistic UI updates for better UX
- Multi-select bulk delete for blocked dates
- Show-only-blocked filter mode

Components:
- src/components/ui/toast.tsx (new)
- scripts/add-featured-column.mjs (new DB migration)
- scripts/README.md (migration documentation)

package.json

@@ -18,6 +18,9 @@
     "pm2:logs": "pm2 logs warme --lines 100 --nostream",
     "pm2:delete": "pm2 delete warme"
   },
+  "migration": {
+    "addFeatured": "node scripts/add-featured-column.mjs"
+  },
   "dependencies": {
     "class-variance-authority": "^0.7.0",
     "clsx": "^2.0.0",