Gate the update button on the selected channel

The confirm button was gated on the device-wide has_updates flag while
the release panel was gated per channel, so picking a channel with no
firmware left the button live and sent the device an update it had
nothing to install. Gate both on the same per-channel lookup, and show
a message where the release panel would be when the channel is empty.

The local source stays exempt: it resolves the release from the Shelly
firmware index rather than from what the device reported.

Author: jfmlima

packages/web/src/components/device-detail/device-actions.tsx

@@ -261,6 +261,15 @@ export function DeviceActions({
                       )}
                     </div>
                   )}
+
+                {updateSource === "internet" &&
+                  !availableUpdates[updateChannel] && (
+                    <div className="p-3 bg-muted rounded-lg text-sm text-muted-foreground">
+                      {t(
+                        "deviceDetail.dialogs.updateFirmware.noReleaseOnChannel",
+                      )}
+                    </div>
+                  )}
               </div>
 
               <DialogFooter>
@@ -279,7 +288,8 @@ export function DeviceActions({
                   }
                   disabled={
                     updateMutation.isPending ||
-                    (updateSource === "internet" && !hasUpdates)
+                    (updateSource === "internet" &&
+                      !availableUpdates[updateChannel])
                   }
                 >
                   {updateMutation.isPending

packages/web/src/i18n/en.json

@@ -410,7 +410,8 @@
         "version": "Version",
         "firmwareUpdate": "Firmware Update",
         "startingUpdate": "Starting Update...",
-        "startUpdate": "Start Update"
+        "startUpdate": "Start Update",
+        "noReleaseOnChannel": "No firmware published on this channel for this device."
       },
       "rebootDevice": {
         "title": "Reboot Device",