review. Dont pass full vm to developer settings

src/settings/DeveloperSettingsTabViewModel.ts

@@ -0,0 +1,43 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { combineLatest } from "rxjs";
+
+import { type CallViewModel } from "../state/CallViewModel/CallViewModel.ts";
+import { type ObservableScope } from "../state/ObservableScope.ts";
+import { createStaticViewModel, type ViewModel } from "../state/ViewModel.ts";
+import { type DeveloperSettingsSnapshot } from "./DeveloperSettingsTab.tsx";
+
+/**
+ * Creates the ViewModel for the developer settings tab while in a call.
+ *
+ * Only the call state the tab actually renders is projected here, so that the
+ * tab does not need to know about the CallViewModel.
+ *
+ * @param scope - ObservableScope that bounds the lifetime of derived behaviors.
+ * @param callModel - The root CallViewModel; provides the key rotation state.
+ */
+export function createDeveloperSettingsTabViewModel(
+  scope: ObservableScope,
+  callModel: CallViewModel,
+): ViewModel<DeveloperSettingsSnapshot> {
+  return {
+    keyRotation$: scope.behavior(
+      combineLatest(
+        [callModel.keyRotationSuppressed$, callModel.participantCount$],
+        (suppressed, participantCount) => ({ suppressed, participantCount }),
+      ),
+    ),
+  };
+}
+
+/**
+ * The ViewModel for the developer settings tab outside of a call (lobby, user
+ * menu), where no call state exists. All call specific fields are `null`.
+ */
+export const outOfCallDeveloperSettingsTabViewModel: ViewModel<DeveloperSettingsSnapshot> =
+  createStaticViewModel<DeveloperSettingsSnapshot>({ keyRotation: null });