refactor(css): extract .tint-candle / .tint-ember utility classes

The candle tint (color-mix accent fill + matching solid border) was inlined
as style="" in five spots across SeriesPassPurchase and EventSeriesTicketCard.
Promote to .tint-candle / .tint-ember utility classes in main.css and replace
the inline styles with the class.

app/components/SeriesPassPurchase.vue

@@ -100,8 +100,7 @@
           <!-- Member Benefits Notice -->
           <div
             v-if="passInfo.ticket.isFree && passInfo.memberInfo?.isMember"
-            class="p-4"
-            style="background: color-mix(in srgb, var(--candle) 15%, transparent); border: 1px solid var(--candle)"
+            class="p-4 tint-candle"
           >
             <div class="flex items-start gap-3">
               <Icon