chore: upgrade i18next 26, prettier 3, fontsource-variable, domhandler 6, lint-staged 17

- i18next 23->26 + react-i18next 15->17
- prettier 2->3, reformat all files
- replace @fontsource/inter with @fontsource-variable/inter 5, update import path
- domhandler 5->6 (aligns with transitive deps)
- lint-staged 16->17

src/app/pages/auth/register/registerUtil.ts

@@ -37,7 +37,7 @@ export type CustomRegisterResponse = {
 export type RegisterResult = [IAuthData, undefined] | [undefined, CustomRegisterResponse];
 export const register = async (
   mx: MatrixClient,
-  requestData: RegisterRequest
+  requestData: RegisterRequest,
 ): Promise<RegisterResult> => {
   const [err, res] = await to<RegisterResponse, MatrixError>(mx.registerRequest(requestData));
 
@@ -130,7 +130,7 @@ export const useRegisterComplete = (data?: CustomRegisterResponse) => {
           withSearchParam<LoginPathSearchParams>(getLoginPath(userServer), {
             username,
           }),
-          { replace: true }
+          { replace: true },
         );
       }
     }