fix: add validation and escaping for Docker network names

Add strict validation for Docker network names using a regex pattern
that matches Docker's naming rules (alphanumeric start, followed by
alphanumeric, dots, hyphens, underscores).

Changes:
- Add DOCKER_NETWORK_PATTERN to ValidationPatterns with helper methods
- Validate network field in Destination creation and update Livewire components
- Add setNetworkAttribute mutator on StandaloneDocker and SwarmDocker models
- Apply escapeshellarg() to all network field usages in shell commands across
  ApplicationDeploymentJob, DatabaseBackupJob, StartService, Init command,
  proxy helpers, and Destination/Show
- Add comprehensive tests for pattern validation and model mutator

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/Models/SwarmDocker.php

@@ -2,10 +2,21 @@
 
 namespace App\Models;
 
+use App\Support\ValidationPatterns;
+
 class SwarmDocker extends BaseModel
 {
     protected $guarded = [];
 
+    public function setNetworkAttribute(string $value): void
+    {
+        if (! ValidationPatterns::isValidDockerNetwork($value)) {
+            throw new \InvalidArgumentException('Invalid Docker network name. Must start with alphanumeric and contain only alphanumeric characters, dots, hyphens, and underscores.');
+        }
+
+        $this->attributes['network'] = $value;
+    }
+
     public function applications()
     {
         return $this->morphMany(Application::class, 'destination');