feat(dms): fix upload response_model, add content_hash migration, storage settings tab, roadmap external storage

frontend/src/api/dms.ts

@@ -27,7 +27,7 @@ export interface DmsFile {
   mime_type: string;
   size_bytes?: number;
   storage_path: string;
-  checksum?: string | null;
+  content_hash?: string | null;
   deleted_at: string | null;
   uploaded_by?: string;
   created_at?: string | null;
@@ -39,6 +39,8 @@ export interface DmsFile {
   size?: number;
   /** @deprecated Use uploaded_by instead */
   created_by?: string;
+  /** @deprecated Use content_hash instead */
+  checksum?: string | null;
 }
 
 export interface FilePermission {