feat(FN-2585): remove top-level remote access toggle

- Remove the standalone remoteEnabled setting from CLI, core settings defaults/types, and dashboard settings APIs/UI
- Treat remote access as enabled when an active provider is selected and that provider is configured as enabled
- Update remote auth and engine lifecycle checks to gate on provider activation instead of a global flag
- Adjust tests and add a changeset documenting the remote access configuration simplification

packages/dashboard/src/remote-auth.ts

@@ -110,12 +110,16 @@ function isRemoteAccessTokenStrategyEnabled(settings: RemoteAccessSettings): boo
   return settings.tokenStrategy.persistent.enabled || settings.tokenStrategy.shortLived.enabled;
 }
 
+function isRemoteProviderEnabled(settings: RemoteAccessSettings): boolean {
+  return Boolean(settings.activeProvider != null && settings.providers[settings.activeProvider]?.enabled);
+}
+
 export function validateRemoteAuthToken(
   rt: string | null | undefined,
   settings: RemoteAccessSettings,
   nowMs: number = Date.now(),
 ): RemoteTokenValidationResult {
-  if (!settings.enabled || !isRemoteAccessTokenStrategyEnabled(settings)) {
+  if (!isRemoteProviderEnabled(settings) || !isRemoteAccessTokenStrategyEnabled(settings)) {
     return { status: "disabled" };
   }