fix(coordinator): retry a command once after a dead-session reconnect

async_send_command's _do_put caught any exception, logged it, and
returned -- no reconnect, no retry, no error the user could see. A
command landing on a session Samsung's firmware closed between polls
(the same 'known device behavior' _async_update_data already
reconnects around) was silently lost, with nothing to do about it but
a manual reload of the device (issue #294).

Mirror the poll path's own recovery: on failure, close the dead
session, pause, and retry the PUT once against a freshly reconnected
one. If that also fails, raise a HomeAssistantError instead of just
logging, so the user gets a visible error rather than a command that
quietly did nothing. The retry runs under the same session lock the
poll path uses, so a write landing mid-reconnect can't race a
concurrent poll cycle rebuilding the same session.

custom_components/localthings/coordinator.py

@@ -15,7 +15,7 @@ from typing import Any
 import cbor2
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.core import HomeAssistant, callback
-from homeassistant.exceptions import ServiceValidationError
+from homeassistant.exceptions import HomeAssistantError, ServiceValidationError
 from homeassistant.helpers import issue_registry as ir
 from homeassistant.helpers.device_registry import DeviceInfo
 from homeassistant.helpers.update_coordinator import DataUpdateCoordinator, UpdateFailed
@@ -1026,18 +1026,42 @@ class LocalThingsCoordinator(DataUpdateCoordinator[dict[str, Any]]):
         )
 
         def _do_put():
+            if self._session is None:
+                self._connect_session()
             sess = self._session
             if sess is None:
                 raise RuntimeError("no session")
             code, _ = sess.post(path_segs, cbor2.dumps(body), timeout=self._POST_TIMEOUT_S)
             self._log.info("PUT %s → code %#04x", write_href, code)
 
-        try:
-            await self.hass.async_add_executor_job(_do_put)
-        except Exception as e:
-            self._log.error("command failed for %s: %s", write_href, e)
-        else:
-            await self.async_request_refresh()
+        # A session Samsung's firmware closed between polls (the same "known
+        # device behavior" _async_update_data reconnects around) previously
+        # sank the PUT here with nothing but a log line -- no retry, no
+        # user-facing error, so the command was silently lost until the next
+        # manual reload (issue #294). Mirror the poll path's own recovery:
+        # one reconnect, one retry, and this time raise on final failure so
+        # the user gets a red toast instead of nothing.
+        #
+        # Locked the same as the poll path so a write landing mid-reconnect
+        # doesn't tear down a session _async_update_data is simultaneously
+        # rebuilding (or vice versa).
+        async with self._session_lock:
+            try:
+                await self.hass.async_add_executor_job(_do_put)
+            except Exception as e:
+                self._log.warning("command failed for %s, reconnecting: %s", write_href, e)
+                await self.hass.async_add_executor_job(self._close_session)
+                await asyncio.sleep(self._RECONNECT_PAUSE_S)
+                try:
+                    await self.hass.async_add_executor_job(_do_put)
+                except Exception as e2:
+                    self._log.error("command failed for %s after reconnect: %s", write_href, e2)
+                    raise HomeAssistantError(
+                        translation_domain=DOMAIN,
+                        translation_key="command_failed",
+                        translation_placeholders={"href": write_href, "error": str(e2)},
+                    ) from e2
+        await self.async_request_refresh()
 
     # ------------------------------------------------------------------
     # Debug raw write (issue #54): a power-user escape hatch for the

custom_components/localthings/translations/cs.json

@@ -1356,6 +1356,9 @@
     },
     "intensive_unavailable_for_cycle": {
       "message": "Intenzivní není u vybraného cyklu k dispozici."
+    },
+    "command_failed": {
+      "message": "Příkaz pro {href} selhal i po opětovném připojení: {error}"
     }
   }
 }

custom_components/localthings/translations/en.json

@@ -1356,6 +1356,9 @@
     },
     "intensive_unavailable_for_cycle": {
       "message": "Intensive isn't available on the selected cycle."
+    },
+    "command_failed": {
+      "message": "The command to {href} failed even after reconnecting: {error}"
     }
   }
 }

custom_components/localthings/translations/es.json

@@ -119,6 +119,9 @@
     },
     "intensive_unavailable_for_cycle": {
       "message": "El modo intensivo no está disponible en el ciclo seleccionado."
+    },
+    "command_failed": {
+      "message": "El comando para {href} falló incluso después de reconectar: {error}"
     }
   },
   "entity": {

custom_components/localthings/translations/it.json

@@ -1356,6 +1356,9 @@
     },
     "intensive_unavailable_for_cycle": {
       "message": "Intensivo non è disponibile per il ciclo selezionato."
+    },
+    "command_failed": {
+      "message": "Il comando per {href} è fallito anche dopo la riconnessione: {error}"
     }
   }
 }

custom_components/localthings/translations/ko.json

@@ -1356,6 +1356,9 @@
     },
     "intensive_unavailable_for_cycle": {
       "message": "선택한 코스에서는 강력 세탁을 사용할 수 없습니다."
+    },
+    "command_failed": {
+      "message": "재연결 후에도 {href} 명령이 실패했습니다: {error}"
     }
   }
 }

custom_components/localthings/translations/nl.json

@@ -1356,6 +1356,9 @@
     },
     "intensive_unavailable_for_cycle": {
       "message": "Intensief is niet beschikbaar voor het geselecteerde programma."
+    },
+    "command_failed": {
+      "message": "Het commando naar {href} is ook na opnieuw verbinden mislukt: {error}"
     }
   }
 }