fix: file preview URLs and milestone web link saving

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/lib/apiClient.ts

@@ -16,6 +16,14 @@ export const apiClient = axios.create({
   },
 });
 
+export function fileViewUrl(fileId: string): string {
+  return `${baseURL}/files/${fileId}/view`;
+}
+
+export function fileDownloadUrl(fileId: string): string {
+  return `${baseURL}/files/${fileId}/download`;
+}
+
 apiClient.interceptors.request.use((config) => {
   if (config.data instanceof FormData) {
     delete config.headers['Content-Type'];