fix(frontend): don't let a failed settings reload escape as a rejection

When a write fails, save() reloads the user so the screen stops showing a
value the server rejected. That reload was unguarded, so if it failed too —
the usual case, since the server that refused the write is often still down
— the rejection escaped save(). Every caller but savePreferredName invokes
it as `void save(...)`, where that surfaces as an unhandled promise
rejection rather than as anything the user can see.

The failure is now contained and the original write error left on screen: it
is the actionable one, and the value shown is the one the user typed anyway.

Author: joschahenningsen

frontend/src/views/SettingsView.vue

@@ -67,10 +67,18 @@ async function save(type: UserSettingType, value: unknown, note: string): Promis
     error.value = message(err);
     // The server rejected the write, so the local value no longer reflects what is
     // stored. Reload rather than leaving a stale value on screen.
-    const user = await auth.load(true);
-    if (user) {
-      settings.value = user.settings;
-      initialName.value = user.settings.preferredName;
+    try {
+      const user = await auth.load(true);
+      if (user) {
+        settings.value = user.settings;
+        initialName.value = user.settings.preferredName;
+      }
+    } catch {
+      // The reload failed too, so the screen keeps the value the user typed. Leave
+      // the write error showing — it is the actionable one — and do not let this
+      // escape: most callers invoke save() as `void save(...)`, where a rejection
+      // surfaces as an unhandled promise rejection rather than as anything a user
+      // can see.
     }
   }
 }