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/composables/useComposants.ts

@@ -10,6 +10,7 @@ export interface Composant {
   id: string
   name: string
   reference?: string | null
+  description?: string | null
   typeComposantId?: string | null
   typeComposant?: { id: string; name?: string } | null
   productId?: string | null