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/client.py

@@ -10,6 +10,7 @@ import asyncio
 import json
 import ssl
 import time
+from contextlib import asynccontextmanager
 from urllib.parse import urlencode
 
 import httpx
@@ -242,9 +243,9 @@ class _Socket:
         return await self.ask(type="supervisor/api", endpoint=endpoint, method="get")
 
 
-async def read_system(url: str, token: str, verify_tls: bool, connect=None) -> dict:
-    """What service.read_health needs, as Home Assistant answered it. `connect`
-    stands in for the websocket in tests."""
+@asynccontextmanager
+async def _signed_in(url: str, token: str, verify_tls: bool, connect):
+    """A signed-in socket. `connect` stands in for the websocket in tests."""
     target = "ws" + url.rstrip("/").removeprefix("http") + "/api/websocket"
     options: dict = {"max_size": MAX_BYTES}
     if target.startswith("wss:") and not verify_tls:
@@ -255,23 +256,37 @@ async def read_system(url: str, token: str, verify_tls: bool, connect=None) -> d
             async with (connect or ws_connect)(target, **options) as ws:
                 socket = _Socket(ws)
                 await socket.sign_in(token)
-                found = {"config": await socket.ask(type="get_config"),
-                         "issues": (await socket.ask(type="repairs/list_issues") or {}).get("issues"),
-                         "resolution": await socket.supervisor("/resolution/info"),
-                         "host": await socket.supervisor("/host/info"), "titles": {}, "boots": {}}
-                domains = sorted({i["domain"] for i in found["issues"] or []})
-                if domains:
-                    titles = await socket.ask(type="frontend/get_translations", language="en",
-                                              category="issues", integration=domains)
-                    found["titles"] = (titles or {}).get("resources") or {}
-                found["addons"] = (await socket.supervisor("/addons") or {}).get("addons")
-                # Whether one should be running is only on its own page, so a running one isn't asked.
-                for addon in found["addons"] or []:
-                    if addon.get("state") != "started":
-                        info = await socket.supervisor(f"/addons/{addon['slug']}/info") or {}
-                        found["boots"][addon["slug"]] = info.get("boot")
-                return found
+                yield socket
     except TimeoutError:
         raise Unreachable(f"Home Assistant's system report didn't arrive within {SYSTEM_READ_SECONDS} s.") from None
     except (OSError, ValueError, KeyError, WebSocketException) as exc:
         raise Unreachable(f"Couldn't read Home Assistant's system report: {exc}") from None
+
+
+async def read_system(url: str, token: str, verify_tls: bool, connect=None) -> dict:
+    """What service.read_health needs, as Home Assistant answered it."""
+    async with _signed_in(url, token, verify_tls, connect) as socket:
+        found = {"config": await socket.ask(type="get_config"),
+                 "issues": (await socket.ask(type="repairs/list_issues") or {}).get("issues"),
+                 "resolution": await socket.supervisor("/resolution/info"),
+                 "host": await socket.supervisor("/host/info"), "titles": {}, "boots": {}}
+        domains = sorted({i["domain"] for i in found["issues"] or []})
+        if domains:
+            titles = await socket.ask(type="frontend/get_translations", language="en",
+                                      category="issues", integration=domains)
+            found["titles"] = (titles or {}).get("resources") or {}
+        found["addons"] = (await socket.supervisor("/addons") or {}).get("addons")
+        # Whether one should be running is only on its own page, so a running one isn't asked.
+        for addon in found["addons"] or []:
+            if addon.get("state") != "started":
+                info = await socket.supervisor(f"/addons/{addon['slug']}/info") or {}
+                found["boots"][addon["slug"]] = info.get("boot")
+        return found
+
+
+async def read_os(url: str, token: str, verify_tls: bool, connect=None) -> dict | None:
+    """The Supervisor's report on the OS: `version`, and `version_pending` while a
+    written update waits for its reboot. None if it isn't answering yet, as just
+    after a boot."""
+    async with _signed_in(url, token, verify_tls, connect) as socket:
+        return await socket.supervisor("/os/info")