send Kodi's watched history from a settings button

Not automatically on the service's first start any more: with several Kodi
installs, only the one whose history counts should send it. The button
("Send this Kodi's watched history to the server") asks first, shows progress
and can be cancelled; sending again is harmless, the server keeps newer state.

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

addon.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <addon id="plugin.video.sklk"
-       version="0.0.24"
+       version="0.0.25"
        name="sklk"
        provider-name="krk">
     <requires>
@@ -20,6 +20,6 @@
             <icon>icon.png</icon>
             <fanart>fanart.jpg</fanart>
         </assets>
-        <news>0.0.24: watched state and resume points kept on the server, shared with other apps</news>
+        <news>0.0.25: sending Kodi's watched history to the server is a button in the settings. 0.0.24: watched state and resume points kept on the server, shared with other apps</news>
     </extension>
 </addon>