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/useApi.ts

@@ -20,11 +20,10 @@ export function useApi() {
 
   const apiCall = async <T = any>(endpoint: string, options: ApiCallOptions = {}): Promise<ApiResponse<T>> => {
     const url = `${API_BASE_URL}${endpoint}`
+    const isFormData = options.body instanceof FormData
     const defaultOptions: ApiCallOptions = {
       credentials: 'include',
-      headers: {
-        'Content-Type': 'application/json',
-      },
+      headers: isFormData ? {} : { 'Content-Type': 'application/json' },
     }
 
     // Ajouter un timeout à la requête
@@ -115,6 +114,13 @@ export function useApi() {
     })
   }
 
+  const postFormData = async <T = any>(endpoint: string, formData: FormData): Promise<ApiResponse<T>> => {
+    return apiCall<T>(endpoint, {
+      method: 'POST',
+      body: formData,
+    })
+  }
+
   const del = async <T = any>(endpoint: string): Promise<ApiResponse<T>> => {
     return apiCall<T>(endpoint, { method: 'DELETE' })
   }
@@ -123,6 +129,7 @@ export function useApi() {
     apiCall,
     get,
     post,
+    postFormData,
     patch,
     put,
     delete: del,