lembas login: a refused sign-in starts a new one; 2.0.0-beta.4

With a stored login for the same server, login only refreshed it; a 401
said "run login again", which did the same again. A SignInRejected from
the refresh now falls through to a fresh device login, which replaces the
old one. The installer's last line points at lembas login.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "lembas-cli",
-  "version": "2.0.0-beta.3",
+  "version": "2.0.0-beta.4",
   "description": "LLeMbas CLI: a terminal coding agent and project manager for a LLeMbas server — OpenTUI, memory, skills, MCP, git-native.",
   "license": "MIT",
   "private": true,