fix(subscription): harden quantity updates and proxy trust behavior

Centralize min/max server limits in Stripe quantity updates and wire them into
Livewire subscription actions with price preview/update handling.

Also improve host/proxy middleware behavior by trusting loopback hosts when FQDN
is set and auto-enabling secure session cookies for HTTPS requests behind
proxies when session.secure is unset.

Includes feature tests for loopback trust and secure cookie auto-detection.

app/Http/Middleware/TrustHosts.php

@@ -91,6 +91,13 @@ class TrustHosts extends Middleware
         // Trust all subdomains of APP_URL as fallback
         $trustedHosts[] = $this->allSubdomainsOfApplicationUrl();
 
+        // Always trust loopback addresses so local access works even when FQDN is configured
+        foreach (['localhost', '127.0.0.1', '[::1]'] as $localHost) {
+            if (! in_array($localHost, $trustedHosts, true)) {
+                $trustedHosts[] = $localHost;
+            }
+        }
+
         return array_filter($trustedHosts);
     }
 }