Derive API origin from VITE_API_BASE_URL for hotlink image src.

Nest api config (baseUrl + baseUrlRoot) so dev cross-origin /i requests work without a separate app-env flag.

frontend/src/views/HotlinkViewerView.vue

@@ -7,6 +7,7 @@
 <script setup lang="ts">
 import { computed } from 'vue';
 import { useRoute } from 'vue-router';
+import { config } from '@/config';
 import { buildHotlinkImagePath } from '@/utils/share/buildHotlinkImagePath';
 
 const route = useRoute();
@@ -19,6 +20,10 @@ const imageSrc = computed((): string | null => {
         return null;
     }
 
-    return buildHotlinkImagePath(uploadId, secret);
+    const { baseUrlRoot } = config.api;
+
+    const path = buildHotlinkImagePath(uploadId, secret);
+
+    return `${baseUrlRoot}${path}`;
 });
 </script>