Refactor(ip-infos): drop the default map images

A card only shows its map once location data has landed, so the bundled
placeholder maps were never meant to be seen, and their labels sat in one
language among many. An empty map URL now renders a same-sized muted box,
which also covers a payload with a country but no coordinates.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/components/IpInfos.vue

@@ -70,8 +70,8 @@ const createDefaultCard = () => ({
   isp: "",
   asn: "",
   asnlink: "",
-  mapUrl: '/res/defaultMap.webp',
-  mapUrl_dark: '/res/defaultMap_dark.webp',
+  mapUrl: "",
+  mapUrl_dark: "",
 });
 
 // IP data cards

frontend/components/ip-infos/LocationMapPanel.vue

@@ -10,21 +10,27 @@
     <span class="font-mono shrink-0 truncate whitespace-nowrap">{{ data.longitude }}, {{ data.latitude
       }}</span>
   </div>
+  <!-- No map URL (no coordinates, or the card is reloading): a same-sized
+       muted box instead of a broken image. -->
   <span>
-    <img :src="isDarkMode ? data.mapUrl_dark : data.mapUrl"
+    <img v-if="mapSrc" :src="mapSrc"
       class="w-full rounded-md border bg-muted aspect-2/1 object-cover" alt="Map">
+    <span v-else class="block w-full rounded-md border bg-muted aspect-2/1" aria-hidden="true"></span>
   </span>
 </template>
 
 <script setup>
+import { computed } from 'vue';
 import { useI18n } from 'vue-i18n';
 import { Earth } from '@lucide/vue';
 
 const { t } = useI18n();
 
-defineProps({
+const props = defineProps({
   // The IP payload — coordinates / mapUrl(_dark).
   data: { type: Object, required: true },
   isDarkMode: { type: Boolean, required: true },
 });
+
+const mapSrc = computed(() => (props.isDarkMode ? props.data.mapUrl_dark : props.data.mapUrl));
 </script>