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/mcp_tools.py

@@ -82,8 +82,9 @@ async def update_home_assistant(entity_id: str) -> dict:
 
     entity_id: from get_home_assistant's `installable`.
 
-    An update restarts Home Assistant or the add-on, and an OS update reboots the
-    machine. Refused while another is under way, or if nothing is waiting there.
+    An update restarts Home Assistant or the add-on. An OS update reads as done
+    once it's written, and takes effect after a reboot, which Steward leaves to a
+    person. Refused while another is under way, or if nothing is waiting there.
     Admin only, as on the page. Recorded in the audit log.
     """
     caller = current_caller()
@@ -104,8 +105,9 @@ async def set_home_assistant_schedule(enabled: bool, weekday: int = 5, at_time:
 
     At each slot Steward installs add-ons, then Core, then the OS, one at a time,
     each after a confirmed backup, stopping at the first failure. A Core update
-    restarts Home Assistant and an OS update reboots the machine, with nobody
-    watching. The first slot is the next one from now. Admin only, and audited.
+    restarts Home Assistant with nobody watching. An OS update takes effect after
+    a reboot, which Steward leaves to a person, and `system.problems` shows it until
+    then. The first slot is the next one from now. Admin only, and audited.
     """
     try:
         weekly.parse_at(at_time)