Add unified MapPanel component for left map panels

- Create MapPanel with white glass header, dark content
- Refactor SelectionPanel to use MapPanel
- Refactor QuotePanel to use MapPanel
- Single source of truth for panel styling

app/components/catalog/MapPanel.vue

@@ -0,0 +1,13 @@
+<template>
+  <div class="flex flex-col h-full -m-4">
+    <!-- Header: белое стекло -->
+    <div class="sticky top-0 z-10 p-4 rounded-t-xl bg-white/90 backdrop-blur-md border-b border-white/20">
+      <slot name="header" />
+    </div>
+
+    <!-- Content: тёмный (наследует контейнер) -->
+    <div class="flex-1 px-4 pt-3 pb-4 overflow-y-auto">
+      <slot />
+    </div>
+  </div>
+</template>