fix(gallery): ruff C408 (dict literal) + panel auto-open on deep-link

Rewrite facets() common/plat_scope as dict literals (C408). Open the refine
panel via a watch on hasRefineFilters rather than reading filter state at
bar-setup time — the parent applies the URL query in its onMounted, after the
bar child has set up, so the initial read was always the default (empty) state.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/components/gallery/GalleryFilterBar.vue

@@ -79,7 +79,7 @@
 </template>
 
 <script setup>
-import { computed, ref } from 'vue'
+import { computed, ref, watch } from 'vue'
 import { useRouter } from 'vue-router'
 import { useApi } from '../../composables/useApi.js'
 import { cloneFilter, filterToQuery, useGalleryStore } from '../../stores/gallery.js'
@@ -117,9 +117,12 @@ const hasActiveFilters = computed(() =>
   hasRefineFilters.value
 )
 
-// Auto-open the panel when arriving with refine filters already in the URL
-// (deep-link / back button) so the active facets are visible, not hidden.
-const refineOpen = ref(hasRefineFilters.value)
+// Auto-open the panel when refine filters are present in the URL (deep-link /
+// back button). The parent applies the query in its onMounted — after this
+// child has set up — so watch for the transition rather than reading the
+// initial (still-default) filter state.
+const refineOpen = ref(false)
+watch(hasRefineFilters, (v) => { if (v) refineOpen.value = true })
 function toggleRefine() {
   // The panel fetches facets itself on mount (and refetches on filter change);
   // opening it is enough.