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/VenueStep/VenueStep.tsx

@@ -139,7 +139,7 @@ export const VenueStep: React.FC<VenueStepProps> = ({
           top: 0,
           zIndex: 1,
           bgcolor: 'background.default',
-          pt: 1.5,
+          pt: 3,
           pb: 1.5,
           mx: { xs: -2, md: -3 },
           px: { xs: 2, md: 3 },
@@ -205,7 +205,16 @@ export const VenueStep: React.FC<VenueStepProps> = ({
       <Box
         role="list"
         aria-label="Available venues"
-        sx={{ display: 'flex', flexDirection: 'column', gap: 2, pb: 3 }}
+        sx={{
+          display: 'flex',
+          flexDirection: 'column',
+          gap: 2,
+          pb: 3,
+          pt: 2,
+          px: { xs: 2, md: 3 },
+          mx: { xs: -2, md: -3 },
+          bgcolor: 'var(--fa-color-surface-subtle)',
+        }}
       >
         {venues.map((venue) => (
           <VenueCard