Shadow the admin-route seam for prototypes and keep new keys out of en-GB

frontend/editor/public/locales/en-GB/translation.toml

@@ -9745,8 +9745,6 @@ apiKeys = "API Keys"
 title = "Developer"
 
 [settings.general]
-appSwitchStyle = "Editor / Processor transition"
-appSwitchStyleDescription = "How the screen animates when you switch between the editor and the processor."
 autoUnzip = "Auto-unzip API responses"
 autoUnzipDescription = "Automatically extract files from ZIP responses"
 autoUnzipFileLimit = "Auto-unzip file limit"
@@ -9792,13 +9790,6 @@ themeSystem = "System"
 title = "General"
 user = "User"
 
-[settings.general.appSwitch]
-axis = "Slide"
-depth = "Depth"
-dissolve = "Dissolve"
-panels = "Panels"
-wipe = "Wipe"
-
 [settings.general.enableFeatures]
 action = "Configure"
 and = "and"

frontend/editor/src/prototypes/routes/adminRouteExtensions.tsx

@@ -0,0 +1,16 @@
+import type { ReactElement } from "react";
+
+/**
+ * Prototypes resolves @app/* through proprietary, but maps no @portal/* of its
+ * own - it ships no portal. Shadowing the seam back to empty keeps proprietary's
+ * copy (and its @portal import) out of this variant's graph entirely.
+ */
+export function getAdminRouteExtensions(): ReactElement[] {
+  return [];
+}
+
+/**
+ * Warms the chunk the admin route-set lives in, so switching into it is not
+ * gated on a network round-trip. No portal in this build, so nothing to warm.
+ */
+export async function preloadAdminRoutes(): Promise<void> {}