ConfirmationStep redesign, page tweaks across wizard

- ConfirmationStep: animated SVG tick, "What happens next" warm card,
  bullet-point layout, contactPhone prop, link-based secondary actions
- VenueStep + ProvidersStep: sticky search bar padding fix, off-white
  bg behind card lists
- IntroStep, CemeteryStep, CrematoriumStep, DateTimeStep: add divider
  under subheading for visual separation
- CoffinsStep: h4 heading (matches VenueStep/ProvidersStep list layout),
  sidebar headings h5 → h6

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/components/pages/CrematoriumStep/CrematoriumStep.tsx

@@ -128,7 +128,7 @@ export const CrematoriumStep: React.FC<CrematoriumStepProps> = ({
         Crematorium
       </Typography>
 
-      <Typography variant="body1" color="text.secondary" sx={{ mb: 5 }}>
+      <Typography variant="body1" color="text.secondary" sx={{ mb: 2 }}>
         {isPrePlanning
           ? 'Review the crematorium details. You can update this later.'
           : isCremationOnly
@@ -136,6 +136,8 @@ export const CrematoriumStep: React.FC<CrematoriumStepProps> = ({
             : 'Confirm the crematorium and let us know about any preferences.'}
       </Typography>
 
+      <Divider sx={{ mb: 4 }} />
+
       <Box
         component="form"
         noValidate