✨(frontend) add API access for 'language' attribute on User model

- allow the language attribute on the user to be updated via API
- add frontend function to update the user language via API
- extend defaults on the test users, to have fixed language in E2E tests
- extend types and variables using the types with the new field

src/frontend/apps/impress/src/features/auth/api/types.ts

@@ -4,10 +4,12 @@
  * @property {string} id - The id of the user.
  * @property {string} email - The email of the user.
  * @property {string} name - The name of the user.
+ * @property {string} language - The language of the user. e.g. 'en-us', 'fr-fr', 'de-de'.
  */
 export interface User {
   id: string;
   email: string;
   full_name: string;
   short_name: string;
+  language: string;
 }

src/frontend/apps/impress/src/features/docs/doc-share/components/DocShareInvitationItem.tsx

@@ -30,6 +30,7 @@ export const DocShareInvitationItem = ({ doc, invitation }: Props) => {
     full_name: invitation.email,
     email: invitation.email,
     short_name: invitation.email,
+    language: 'en-us',
   };
 
   const { toast } = useToastProvider();

src/frontend/apps/impress/src/features/docs/doc-share/components/DocShareModal.tsx

@@ -132,6 +132,7 @@ export const DocShareModal = ({ doc, onClose }: Props) => {
       full_name: '',
       email: userQuery,
       short_name: '',
+      language: '',
     };
 
     const hasEmailInUsers = users.some((user) => user.email === userQuery);

src/frontend/apps/impress/src/features/language/api/useChangeUserLanguage.tsx

@@ -0,0 +1,45 @@
+import { useMutation, useQueryClient } from '@tanstack/react-query';
+
+import { APIError, errorCauses, fetchAPI } from '@/api';
+import { User } from '@/features/auth/api/types';
+
+export interface ChangeUserLanguageParams {
+  userId: User['id'];
+  language: User['language'];
+}
+
+export const changeUserLanguage = async ({
+  userId,
+  language,
+}: ChangeUserLanguageParams): Promise<User> => {
+  const response = await fetchAPI(`users/${userId}/`, {
+    method: 'PATCH',
+    body: JSON.stringify({
+      language,
+    }),
+  });
+
+  if (!response.ok) {
+    throw new APIError(
+      `Failed to change the user language to ${language}`,
+      await errorCauses(response, {
+        value: language,
+        type: 'language',
+      }),
+    );
+  }
+
+  return response.json() as Promise<User>;
+};
+
+export function useChangeUserLanguage() {
+  const queryClient = useQueryClient();
+  return useMutation<User, APIError, ChangeUserLanguageParams>({
+    mutationFn: changeUserLanguage,
+    onSuccess: () => {
+      void queryClient.invalidateQueries({
+        queryKey: ['change-user-language'],
+      });
+    },
+  });
+}