Address remaining PR review comments

- Fix getAllInstances to handle empty instance array without throwing
- Persist updated token expiry timestamps to disk after refresh
- Mark internal httpJson helpers as @internal instead of @public

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
Made-with: Cursor

packages/cli-module-auth/src/lib/storage.ts

@@ -96,6 +96,9 @@ export async function getAllInstances(): Promise<{
   selected: StoredInstance | undefined;
 }> {
   const { instances } = await readAll();
+  if (instances.length === 0) {
+    return { instances: [], selected: undefined };
+  }
   const selected = instances.find(i => i.selected) ?? instances[0];
   return {
     instances: instances.map(i => ({