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/shared/utils/documentDisplayUtils.ts

@@ -19,26 +19,32 @@ export const formatSize = (size: number | null | undefined): string => {
   return `${formatted.toFixed(1)} ${units[index]}`
 }
 
+const resolveUrl = (doc: any): string => doc?.fileUrl || doc?.path || ''
+
 export const shouldInlinePdf = (doc: any): boolean => {
-  if (!doc || !isPdfDocument(doc) || !doc.path) return false
+  if (!doc || !isPdfDocument(doc)) return false
+  const url = resolveUrl(doc)
+  if (!url) return false
   if (typeof doc.size === 'number' && doc.size > PDF_PREVIEW_MAX_BYTES) return false
   return true
 }
 
 export const appendPdfViewerParams = (src: string): string => {
-  if (!src || src.startsWith('data:')) return src || ''
+  if (!src) return ''
+  if (src.startsWith('data:')) return src
   if (src.includes('#')) return `${src}&toolbar=0&navpanes=0`
   return `${src}#toolbar=0&navpanes=0`
 }
 
 export const documentPreviewSrc = (doc: any): string => {
-  if (!doc?.path) return ''
-  if (isPdfDocument(doc)) return appendPdfViewerParams(doc.path)
-  return doc.path
+  const url = resolveUrl(doc)
+  if (!url) return ''
+  if (isPdfDocument(doc)) return appendPdfViewerParams(url)
+  return url
 }
 
 export const documentThumbnailClass = (doc: any): string => {
-  if (shouldInlinePdf(doc) || (isImageDocument(doc) && doc?.path)) return 'h-24 w-20'
+  if (shouldInlinePdf(doc) || (isImageDocument(doc) && resolveUrl(doc))) return 'h-24 w-20'
   return 'h-16 w-16'
 }
 
@@ -52,8 +58,14 @@ export const documentIcon = (doc: any): FileIconResult =>
   getFileIcon({ name: doc?.filename || doc?.name, mime: doc?.mimeType })
 
 export const downloadDocument = (doc: any): void => {
-  if (!doc?.path) return
-  const target = String(doc.path)
+  // Prefer dedicated download endpoint
+  if (doc?.downloadUrl) {
+    window.open(doc.downloadUrl, '_blank')
+    return
+  }
+  // Fallback for legacy data: URIs during migration
+  const target = resolveUrl(doc)
+  if (!target) return
   if (target.startsWith('data:')) {
     const link = document.createElement('a')
     link.href = target