refactor(operator): group on-call/notifications/profile flush right in topbar

Replace the inert .spacer (flex: 0 0 auto, did nothing) with a real .right
wrapper using margin-left: auto. The on-call indicator, notifications bell,
and UserMenu now form a single right-aligned cluster instead of sitting
loose in the header flex flow.

apps/operator/components/OpTopbar.vue

@@ -24,8 +24,7 @@ const ENVS = {
       <span class="kbd">⌘K</span>
     </button>
 
-    <span class="spacer" />
+    <div class="right">
-
       <span class="oncall" :class="{ active: oncall }">
         <StatusDot :color="oncall ? 'var(--accent)' : 'var(--text-mute)'" :size="6" :glow="false" />
         <Mono :dim="!oncall">{{ oncall ? 'on-call · Mikkel' : 'no active page' }}</Mono>
@@ -37,6 +36,7 @@ const ENVS = {
       </button>
 
       <UserMenu />
+    </div>
   </header>
 </template>
 
@@ -98,7 +98,13 @@ header {
   flex-shrink: 0;
 }
 
-.spacer { flex: 0 0 auto; }
+.right {
+  margin-left: auto;
+  display: flex;
+  align-items: center;
+  gap: 12px;
+  flex-shrink: 0;
+}
 
 .oncall {
   display: inline-flex;