fix(homeassistant): storage reads used of total with its percentage, and an OS update is said to wait on a reboot (#6753, #6754)

The tile shows Home Assistant's own used figure beside the total, so it matches
Home Assistant's storage page. An OS update doesn't reboot the machine: Supervisor
writes the image, reports the new version and raises a repair asking for a reboot.
The confirmation, schedule warning, MCP docs and plugin docs now say so.

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

plugins/homeassistant/templates/homeassistant/index.html

@@ -37,8 +37,7 @@
 
 <div class="stat-strip">
   {{ stat_tile("System problems", problems|length if health.repairs_read else "—", state="degraded" if problems else none) }}
-  {{ stat_tile("Storage", (health.disk_total_gb ~ " GB") if health.disk_total_gb else "—",
-               hint=("%.0f%% full"|format(100 - health.disk_free_pct)) if health.disk_free_pct is number else none) }}
+  {{ stat_tile("Storage", ("%s of %s GB (%.0f%%)"|format(health.disk_used_gb, health.disk_total_gb, health.disk_used_pct)) if health.disk_used_pct is number else "—") }}
   {{ stat_tile("Updates waiting", installable|length if connection.last_ok_at else "—") }}
   {{ stat_tile("Last good backup", (backup_at|ago) if backup_at else "—", state="degraded" if backup_tone == 'warn' else none) }}
   {{ stat_tile("Next backup", (backup_next|ago) if backup_next else "—") }}
@@ -78,7 +77,7 @@
         {% if admin %}<td style="text-align:right;">
           {% if connection.can_install and not under_way and not connection.refused and not u.in_progress %}
           <form method="post" action="/plugins/homeassistant/install"
-                data-confirm="Install {{ u.title }} {{ u.latest }}? Steward takes a backup first and won't install without it. {{ 'Home Assistant restarts.' if u.kind == 'core' else ('The machine reboots.' if u.kind == 'os' else 'The add-on restarts.') }}">{{ csrf_field() }}
+                data-confirm="Install {{ u.title }} {{ u.latest }}? Steward takes a backup first and won't install without it. {{ 'Home Assistant restarts.' if u.kind == 'core' else ('It takes effect once you reboot the machine, which Steward leaves to you.' if u.kind == 'os' else 'The add-on restarts.') }}">{{ csrf_field() }}
             <input type="hidden" name="entity_id" value="{{ u.entity_id }}">
             <button class="btn btn-sm" type="submit">Install</button>
           </form>
@@ -104,7 +103,7 @@
   {% endif %}
   {% if plan and plan.stopped %}<p class="tone-warn">The last run stopped early. {{ plan.stopped }}</p>{% endif %}
   {% if admin %}
-  <p class="tone-warn">A Core update restarts Home Assistant and an OS update reboots the machine, with nobody there to watch. An update can also change how automations behave.</p>
+  <p class="tone-warn">A Core update restarts Home Assistant with nobody there to watch, and an update can change how automations behave. An OS update takes effect only once you reboot the machine: Steward leaves that to you, and shows it under System until it's done.</p>
   <form method="post" action="/plugins/homeassistant/schedule" style="display:flex;flex-wrap:wrap;gap:0.75rem;align-items:flex-end;">{{ csrf_field() }}
     <label style="display:flex;gap:0.5rem;align-items:center;cursor:pointer;margin-bottom:0.4rem;">
       <input type="checkbox" name="enabled" value="on"{% if plan and plan.enabled %} checked{% endif %}> Install on a schedule