Errors now show as toasts in the bottom right corner

web/README.md

@@ -81,10 +81,13 @@ token when it first needs it, and a new one if a request is refused for it.
 - `src/primitives/createLiveUpdates.ts` – applies the backend's events
 - `src/primitives/createOpportunityAnnotations.ts` – changing marks and hiding
   (applied at once, undone if the save fails)
+- `src/primitives/createToasts.ts` – the toasts errors are shown in, bottom
+  right, for 15 seconds or until dismissed
 - `src/lib/filterOpportunities.ts` – search and filter logic
 - `src/lib/opportunities.ts` – merging changed opportunities into the list
 - `src/components/` – FilterPanel, ClassificationPicker, OpportunityTable,
-  MarkMenu, ThemeToggle; `styles.ts` holds shared Tailwind class strings
+  MarkMenu, ThemeToggle, ToastList; `styles.ts` holds shared Tailwind class
+  strings
 
 Theme colours and the font are set in the `@theme` block of `src/index.css`.