Optimistic Discover decisions and deck refill (#108)

Co-authored-by: orchestrator-agent <20+orchestrator-agent@code.cubecraftcreations.com>

web/src/ui/ErrorBanner.test.tsx

@@ -24,6 +24,12 @@ describe('ErrorBanner', () => {
     expect(screen.getByRole('button', { name: 'Rebuild week' })).toBeInTheDocument()
   })
 
+  it('has no button without onRetry', () => {
+    render(<ErrorBanner>That was done already.</ErrorBanner>)
+    expect(screen.getByRole('alert')).toHaveTextContent('That was done already.')
+    expect(screen.queryByRole('button')).not.toBeInTheDocument()
+  })
+
   it('is a neutral-100 card with grape-700 text', () => {
     render(<ErrorBanner onRetry={() => {}}>Offline</ErrorBanner>)
     expect(declaredStyle(screen.getByRole('alert')).background).toBe('var(--color-neutral-100)')

web/src/ui/ErrorBanner.tsx

@@ -6,16 +6,18 @@ import styles from './ErrorBanner.module.css'
 export type ErrorBannerProps = {
   // What went wrong, in the caller's words.
   children: ReactNode
-  onRetry: () => void
+  // What Retry does; without it there is nothing to retry and no button.
+  onRetry?: () => void
   retryLabel?: string
 }
 
-// Muted neutral-100 card with grape-700 text and a Retry button.
+// Muted neutral-100 card with grape-700 text and, given onRetry, a Retry
+// button.
 export function ErrorBanner({ children, onRetry, retryLabel = 'Retry' }: ErrorBannerProps) {
   return (
     <Card tone="muted" role="alert" className={styles.banner}>
       <p className={styles.message}>{children}</p>
-      <Button onClick={onRetry}>{retryLabel}</Button>
+      {onRetry !== undefined && <Button onClick={onRetry}>{retryLabel}</Button>}
     </Card>
   )
 }