CompareBar: bump bottom offset to clear HelpBar properly

Previous offset used theme.spacing(9) assuming 8px MUI default base —
but the FA theme uses a 4px base, so spacing(9) was only 36px and
the pill still sat 3px below the ~40px HelpBar. Bumped to spacing(16)
(64px) for a clean 25px gap above HelpBar on both mobile and desktop.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/molecules/CompareBar/CompareBar.tsx

@@ -62,9 +62,10 @@ export const CompareBar = React.forwardRef<HTMLDivElement, CompareBarProps>(
           sx={[
             (theme: Theme) => ({
               position: 'fixed',
-              // Clear the sticky HelpBar (~56px + 16px breathing) so the
-              // pill doesn't overlap it.
-              bottom: theme.spacing(9),
+              // Clear the sticky HelpBar (~40px tall) with ~25px of
+              // breathing space. FA theme.spacing uses a 4px base, so
+              // spacing(16) = 64px.
+              bottom: theme.spacing(16),
               // Centre via auto-margin rather than `left:50%; translateX(-50%)`
               // — Slide (the wrapper) animates via transform, which would
               // otherwise clobber the centering transform.