feat: move environment selector into TopBar (DS v0.1.30)

Update @cameleer/design-system to v0.1.30 which accepts ReactNode
for the environment prop. Move EnvironmentSelector from standalone
div into TopBar, rendering between theme toggle and user menu.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/components/LayoutShell.tsx

@@ -702,7 +702,13 @@ function LayoutContent() {
     <AppShell sidebar={sidebarElement}>
       <TopBar
         breadcrumb={breadcrumb}
-        environment={selectedEnv}
+        environment={environments.length > 0 ? (
+          <EnvironmentSelector
+            environments={environments}
+            value={selectedEnv}
+            onChange={setSelectedEnv}
+          />
+        ) : undefined}
         user={username ? { name: username } : undefined}
         onLogout={handleLogout}
       />
@@ -717,16 +723,6 @@ function LayoutContent() {
         data={searchData}
       />
 
-      {!isAdminPage && environments.length > 0 && (
-        <div style={{ display: 'flex', justifyContent: 'flex-end', padding: '4px 1.5rem 0' }}>
-          <EnvironmentSelector
-            environments={environments}
-            value={selectedEnv}
-            onChange={setSelectedEnv}
-          />
-        </div>
-      )}
-
       {!isAdminPage && (
         <ContentTabs active={scope.tab} onChange={setTab} scope={scope} />
       )}