fix(deploy): keep preview and build server hosts out of build --add-host

Preview containers (-pr-<id>) came and went with pull requests and
invalidated the build cache of every app on the network. A build server
got the IPs of the deployment server network, which it cannot reach.
Add a per-app setting to turn off network hosts during the build.

Closes #12452

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

database/migrations/2026_11_05_163404_add_include_network_hosts_in_build_to_application_settings.php

@@ -0,0 +1,32 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        if (! Schema::hasColumn('application_settings', 'include_network_hosts_in_build')) {
+            Schema::table('application_settings', function (Blueprint $table) {
+                $table->boolean('include_network_hosts_in_build')->default(true)->after('include_source_commit_in_build');
+            });
+        }
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        if (Schema::hasColumn('application_settings', 'include_network_hosts_in_build')) {
+            Schema::table('application_settings', function (Blueprint $table) {
+                $table->dropColumn('include_network_hosts_in_build');
+            });
+        }
+    }
+};