feat(navigation) : preserve list state in URL and use browser history for back buttons

Add useUrlState composable to sync page, search, sort and filter state
with URL query params. Back/forward navigation now restores the exact
list position. Replace hardcoded NuxtLink back buttons with
router.back() across all create/edit pages. Fix documents attachment
filter that checked non-existent ID fields instead of relation objects.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/pages/documents.vue

@@ -132,6 +132,7 @@
 <script setup>
 import { ref, computed, onMounted } from 'vue'
 import { useDocuments } from '~/composables/useDocuments'
+import { useUrlState } from '~/composables/useUrlState'
 import { getFileIcon } from '~/utils/fileIcons'
 import { canPreviewDocument } from '~/utils/documentPreview'
 import { formatFrenchDate } from '~/utils/date'
@@ -140,8 +141,10 @@ import IconLucideFileSearch from '~icons/lucide/file-search'
 
 const { documents, loading, loadDocuments } = useDocuments()
 
-const searchTerm = ref('')
-const attachmentFilter = ref('all')
+const { q: searchTerm, filter: attachmentFilter } = useUrlState({
+  q: { default: '', debounce: 300 },
+  filter: { default: 'all' },
+})
 const previewDocument = ref(null)
 const previewVisible = ref(false)
 
@@ -156,10 +159,10 @@ const filteredDocuments = computed(() => {
   return documents.value.filter((document) => {
     const matchesFilter =
       filter === 'all' ||
-      (filter === 'site' && document.siteId) ||
-      (filter === 'machine' && document.machineId) ||
-      (filter === 'composant' && document.composantId) ||
-      (filter === 'piece' && document.pieceId)
+      (filter === 'site' && document.site) ||
+      (filter === 'machine' && document.machine) ||
+      (filter === 'composant' && document.composant) ||
+      (filter === 'piece' && document.piece)
 
     if (!matchesFilter) { return false }