fix: prevent fight view scrolling on mobile with tab bar

All pages used h-[calc(100dvh-4rem)] which only subtracted the top
navbar but ignored the mobile tab bar's pb-14 bottom padding, causing
content to overflow and scroll. Changed all pages to h-full so they
fill the flex parent (main element) which already handles both the
navbar and tab bar spacing correctly.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/pages/LeaderboardPage.vue

@@ -78,7 +78,7 @@ onUnmounted(() => {
 </script>
 
 <template>
-  <div class="h-[calc(100dvh-4rem)] flex flex-col px-6 py-6 overflow-hidden">
+  <div class="h-full flex flex-col px-6 py-6 overflow-hidden">
     <div class="max-w-4xl mx-auto w-full flex flex-col flex-1 min-h-0">
 
       <!-- Header -->