fix(server-transfer): harden import on Cloud and stop archives from using server slots

- Rate limit the import check probe and refuse private, loopback, and
  link-local targets on Cloud.
- Rate limit the SSH validation that an import starts, like other
  server validations.
- Count only managed servers for the server limit, the limit check job,
  and the subscription page. Archives of transferred servers are left out.
- Do not show the name of another team's archived server in the import check.

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

app/Models/Team.php

@@ -158,7 +158,7 @@ class Team extends Model implements SendsDiscord, SendsEmail, SendsPushover, Sen
             return true;
         }
         $serverLimit = Team::serverLimit($team);
-        $servers = $team->servers()->count();
+        $servers = $team->managedServers()->count();
 
         return $servers >= $serverLimit;
     }
@@ -192,7 +192,7 @@ class Team extends Model implements SendsDiscord, SendsEmail, SendsPushover, Sen
 
     public function serverOverflow()
     {
-        if (Team::serverLimit($this) < $this->servers->count()) {
+        if (Team::serverLimit($this) < $this->managedServers()->count()) {
             return true;
         }
 
@@ -392,6 +392,14 @@ class Team extends Model implements SendsDiscord, SendsEmail, SendsPushover, Sen
         return $this->hasMany(Server::class);
     }
 
+    /**
+     * Servers that use a server slot. Archives of transferred servers are left out.
+     */
+    public function managedServers()
+    {
+        return $this->servers()->notTransferredAway();
+    }
+
     public function usesSwarm(): bool
     {
         return $this->servers()