fix(nav): keep tab active on nested routes (#117)

Fixes #26

Mobile tab active-state used exact route matching, so tabs lost their
highlight on descendant routes. Adds `fuzzy: true` to `useMatchRoute` so
parent tabs stay highlighted on nested routes, matching the desktop
`Link`'s existing behavior.

## Verification
- Navigate to a set detail page (`.../sets/$setSlug`) on mobile; the
Sets tab stays highlighted.
- Navigate to `.../schedule/timeline` or `.../schedule/list` on mobile;
the Schedule tab stays highlighted.
- Switch between tabs (Sets, Schedule, Map, Info, Social, Explore);
exactly one tab is highlighted at a time, no cross-activation.
- Desktop tab bar behavior is unchanged (still uses `Link activeProps`).

---
_Generated by [Claude
Code](https://claude.ai/code/session_014iiisPt8nyYMGcYfh9p5yo)_

Co-authored-by: Claude <noreply@anthropic.com>

Author: chiptus

src/pages/EditionView/TabNavigation/MobileTabButton.tsx

@@ -15,7 +15,7 @@ export function MobileTabButton({ config }: TabButtonProps) {
     from: "/festivals/$festivalSlug/editions/$editionSlug",
   });
   const matchRoute = useMatchRoute();
-  const isActive = !!matchRoute({ to: tabRoutes[config.key] });
+  const isActive = !!matchRoute({ to: tabRoutes[config.key], fuzzy: true });
 
   return (
     <Link