feat: add comprehensive environment variable parsing with nested resolution and hardcoded variable detection

This commit introduces advanced environment variable handling capabilities including:
- Nested environment variable resolution with circular dependency detection
- Extraction of hardcoded environment variables from docker-compose.yml
- New ShowHardcoded Livewire component for displaying detected variables
- Enhanced UI for better environment variable management

The changes improve the user experience by automatically detecting and displaying
environment variables that are hardcoded in docker-compose files, allowing users
to override them if needed. The nested variable resolution ensures complex variable
dependencies are properly handled.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

bootstrap/helpers/shared.php

@@ -3692,3 +3692,55 @@ function verifyPasswordConfirmation(mixed $password, ?Livewire\Component $compon
 
     return true;
 }
+
+/**
+ * Extract hard-coded environment variables from docker-compose YAML.
+ *
+ * @param  string  $dockerComposeRaw  Raw YAML content
+ * @return \Illuminate\Support\Collection Collection of arrays with: key, value, comment, service_name
+ */
+function extractHardcodedEnvironmentVariables(string $dockerComposeRaw): \Illuminate\Support\Collection
+{
+    if (blank($dockerComposeRaw)) {
+        return collect([]);
+    }
+
+    try {
+        $yaml = \Symfony\Component\Yaml\Yaml::parse($dockerComposeRaw);
+    } catch (\Exception $e) {
+        // Malformed YAML - return empty collection
+        return collect([]);
+    }
+
+    $services = data_get($yaml, 'services', []);
+    if (empty($services)) {
+        return collect([]);
+    }
+
+    // Extract inline comments from raw YAML
+    $envComments = extractYamlEnvironmentComments($dockerComposeRaw);
+
+    $hardcodedVars = collect([]);
+
+    foreach ($services as $serviceName => $service) {
+        $environment = collect(data_get($service, 'environment', []));
+
+        if ($environment->isEmpty()) {
+            continue;
+        }
+
+        // Convert environment variables to key-value format
+        $environment = convertToKeyValueCollection($environment);
+
+        foreach ($environment as $key => $value) {
+            $hardcodedVars->push([
+                'key' => $key,
+                'value' => $value,
+                'comment' => $envComments[$key] ?? null,
+                'service_name' => $serviceName,
+            ]);
+        }
+    }
+
+    return $hardcodedVars;
+}