fix(ui): Admin login could hang forever on "Logging in..."

AdminScreen's LOGIN phase had no timeout, unlike its COMMAND phase
(_cmd_deadline_ms). If a login reply never arrived -- most commonly a
saved password gone stale after the remote node's password changed,
silently dropped instead of nacked -- the screen stayed stuck with only
a manual Cancel to escape.

sendRoomLogin() now returns the same est_timeout sendAdminCommand()
already exposes; AdminScreen uses it to arm a deadline (poll(),
mirroring the COMMAND-phase pattern) that forgets the stale password
and returns to the picker on expiry, same as an explicit login
rejection already does.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

release-notes.md

@@ -1,3 +1,11 @@
+## Unreleased
+
+### Fixes
+
+- **Tools › Admin login could get stuck on "Logging in..." forever** if the remote node never sent back a reply — most commonly after its admin/room password was changed, since the on-device UI auto-retries the old saved password with no timeout to fall back on. It now gives up after the same estimated-timeout window the rest of Admin's commands use, forgets the stale saved password, and returns you to the picker to try again with the new one.
+
+---
+
 ## MeshCore Solo Companion Firmware v1.23
 
 ### What's new