fix(auth): restore metadata editing lost to the 3.5.0 library roles

Promote Viewer grants to Editor on book libraries for non-superusers who hold Edit metadata but
can edit nowhere, which is how every such account was left after the upgrade. Accounts with any
Editor or Owner role are left alone. The Users drawer now says where Edit metadata takes effect,
read from a new GET /users/:id/library-access route.

Closes #1902

packages/types/src/library.ts

@@ -148,6 +148,11 @@ export interface LibraryAccessEntry {
   accessLevel: AccessLevel;
 }
 
+export interface UserLibraryGrant {
+  libraryId: number;
+  accessLevel: AccessLevel;
+}
+
 export interface DefaultLibraryAccessConfig {
   libraryIds: number[];
 }