feat(documents): migrate storage to filesystem, add server-side pagination

- Replace Base64 data URIs with file-based storage served via dedicated endpoints
- Add DocumentPreviewModal navigation, DocumentThumbnail fileUrl support
- Refactor documents page with server-side pagination, search, sort and filters
- Update all components to use fileUrl/downloadUrl instead of raw path
- Add pagination composable support (total, page, itemsPerPage, attachmentFilter)

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

app/components/sites/SiteEditModal.vue

@@ -57,8 +57,8 @@
                 <div class="flex items-center gap-3 text-sm">
                   <div class="h-14 w-14 flex-shrink-0 overflow-hidden rounded-md border border-base-200 bg-base-200/70 flex items-center justify-center">
                     <img
-                      v-if="isImageDocument(document) && document.path"
-                      :src="document.path"
+                      v-if="isImageDocument(document) && (document.fileUrl || document.path)"
+                      :src="document.fileUrl || document.path"
                       class="h-full w-full object-cover"
                       :alt="`Aperçu de ${document.name}`"
                     >