Frontend cleanups

Mainly:

 - better handling of GraphQL errors
 - better logout state
 - dependencies update
 - a way to end browser sessions in the GraphQL API

crates/graphql/src/mutations/mod.rs

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+mod browser_session;
 mod compat_session;
 mod oauth2_session;
 mod user_email;
@@ -24,6 +25,7 @@ pub struct Mutation(
     user_email::UserEmailMutations,
     oauth2_session::OAuth2SessionMutations,
     compat_session::CompatSessionMutations,
+    browser_session::BrowserSessionMutations,
 );
 
 impl Mutation {