fix(team): mark servers unreachable when subscription ends

Set unreachable_count to 3 and unreachable_notification_sent to true
on all team servers in subscriptionEnded(), so the existing cleanup
command can pick them up after the 7-day grace period.

Also adds feature tests for the subscription-ended cleanup flow and
casts server IP to string in existing unreachable server tests to fix
type comparison.

app/Models/Team.php

@@ -233,6 +233,9 @@ class Team extends Model implements SendsDiscord, SendsEmail, SendsPushover, Sen
                 'is_reachable' => false,
             ]);
             ServerReachabilityChanged::dispatch($server);
+            $server->unreachable_count = 3;
+            $server->unreachable_notification_sent = true;
+            $server->save();
         }
     }
 
@@ -344,5 +347,4 @@ class Team extends Model implements SendsDiscord, SendsEmail, SendsPushover, Sen
     {
         return $this->hasOne(WebhookNotificationSettings::class);
     }
-
 }