fix(server): handle limit edge case and IPv6 allowlist dedupe

Update server limit enforcement to re-enable force-disabled servers when the
team is at or under its limit (`<= 0` condition).

Improve allowlist validation and matching by:
- supporting IPv6 CIDR mask ranges up to `/128`
- adding IPv6-aware CIDR matching in `checkIPAgainstAllowlist`
- normalizing/deduplicating redundant allowlist entries before saving

Add feature tests for `ServerLimitCheckJob` covering under-limit, at-limit,
over-limit, and no-op scenarios.

app/Jobs/ServerLimitCheckJob.php

@@ -38,7 +38,7 @@ class ServerLimitCheckJob implements ShouldBeEncrypted, ShouldQueue
                     $server->forceDisableServer();
                     $this->team->notify(new ForceDisabled($server));
                 });
-            } elseif ($number_of_servers_to_disable === 0) {
+            } elseif ($number_of_servers_to_disable <= 0) {
                 $servers->each(function ($server) {
                     if ($server->isForceDisabled()) {
                         $server->forceEnableServer();

app/Livewire/Settings/Advanced.php

@@ -95,7 +95,9 @@ class Advanced extends Component
                     // Check if it's valid CIDR notation
                     if (str_contains($entry, '/')) {
                         [$ip, $mask] = explode('/', $entry);
-                        if (filter_var($ip, FILTER_VALIDATE_IP) && is_numeric($mask) && $mask >= 0 && $mask <= 32) {
+                        $isIpv6 = filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) !== false;
+                        $maxMask = $isIpv6 ? 128 : 32;
+                        if (filter_var($ip, FILTER_VALIDATE_IP) && is_numeric($mask) && $mask >= 0 && $mask <= $maxMask) {
                             return $entry;
                         }
                         $invalidEntries[] = $entry;
@@ -111,7 +113,7 @@ class Advanced extends Component
                     $invalidEntries[] = $entry;
 
                     return null;
-                })->filter()->unique();
+                })->filter()->values()->all();
 
                 if (! empty($invalidEntries)) {
                     $this->dispatch('error', 'Invalid IP addresses or subnets: '.implode(', ', $invalidEntries));
@@ -119,13 +121,15 @@ class Advanced extends Component
                     return;
                 }
 
-                if ($validEntries->isEmpty()) {
+                if (empty($validEntries)) {
                     $this->dispatch('error', 'No valid IP addresses or subnets provided');
 
                     return;
                 }
 
-                $this->allowed_ips = $validEntries->implode(',');
+                $validEntries = deduplicateAllowlist($validEntries);
+
+                $this->allowed_ips = implode(',', $validEntries);
             }
 
             $this->instantSave();

app/Rules/ValidIpOrCidr.php

@@ -45,7 +45,10 @@ class ValidIpOrCidr implements ValidationRule
 
                 [$ip, $mask] = $parts;
 
-                if (! filter_var($ip, FILTER_VALIDATE_IP) || ! is_numeric($mask) || $mask < 0 || $mask > 32) {
+                $isIpv6 = filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) !== false;
+                $maxMask = $isIpv6 ? 128 : 32;
+
+                if (! filter_var($ip, FILTER_VALIDATE_IP) || ! is_numeric($mask) || $mask < 0 || $mask > $maxMask) {
                     $invalidEntries[] = $entry;
                 }
             } else {