feat(homeassistant): a scheduled OS update reboots the machine and is done once the new version runs (#6755)

Home Assistant writes an OS update and leaves the reboot to someone, so a scheduled
one never finished unattended. The schedule now asks for the reboot once, follows it
through Home Assistant going away, and counts it done when the Supervisor reports a
different version with nothing pending. A machine that doesn't come back or falls
back to the old version fails after 20 minutes, which ends the slot and raises
update_failed. Install on the page and through MCP still leave the reboot to the person.

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

plugins/homeassistant/routes.py

@@ -23,7 +23,7 @@ from steward.models.users import User, UserRole
 from . import client, schedule
 from .models import HomeAssistantConnection, HomeAssistantSchedule, HomeAssistantUpdate
 from .service import STALE_BACKUP_HOURS, backup_age_hours, backup_verdict, installable, parse_moment, problems_open
-from .updates import CannotStart, start_update
+from .updates import UNDER_WAY, CannotStart, start_update
 
 logger = logging.getLogger(__name__)
 
@@ -72,7 +72,7 @@ async def _render_index(error: str | None = None, status: int = 200):
         installable=installable(connection),
         others=[u for u in updates if u["waiting"] and not u["kind"]],
         current=[u for u in updates if not u["waiting"] and u["kind"]],
-        runs=runs, under_way=next((r for r in runs if r.state in ("backing_up", "installing")), None),
+        runs=runs, under_way=next((r for r in runs if r.state in UNDER_WAY), None),
         backup=backup, backup_tone=tone, backup_says=backup_says,
         backup_at=parse_moment(backup.get("last_ok")), backup_next=parse_moment(backup.get("next")),
         backup_age=backup_age_hours(backup, now), stale_hours=STALE_BACKUP_HOURS,