UI fixes: header height, map color, panel scroll

- MainNavigation: fixed min-height to prevent jumping on mode switch
- CatalogMap: default pointColor changed from green to orange (#f97316)
- CatalogPage: panel scroll on entire container, not inner
- SelectionPanel: sticky header and search, removed inner scroll

app/components/navigation/MainNavigation.vue

@@ -30,7 +30,7 @@
       </div>
 
       <!-- Center: Search input (transforms based on mode) -->
-      <div class="flex-1 flex flex-col items-center max-w-2xl mx-auto gap-2">
+      <div class="flex-1 flex flex-col items-center max-w-2xl mx-auto gap-2 min-h-[72px] justify-center">
         <!-- Quote mode: Segmented input like Airbnb -->
         <template v-if="catalogMode === 'quote'">
           <div class="flex items-center gap-3 w-full">