feat: Add configurable real IP forwarding for bare-metal clusters

Implement a new nginx.forwardRealIP configuration flag to enable/disable
real client IP extraction from X-Forwarded-For headers on bare-metal clusters.

Changes:
- Added nginx.forwardRealIP.enabled flag (default: false) to values.yaml
- Added nginx.forwardRealIP.trustedProxies list for flexible proxy IP ranges
- Updated Nginx configmap to conditionally apply real IP extraction settings
- Updated FastCGI parameters to use real IP when enabled, direct connection IP otherwise
- Updated WordPress wp-config.php to conditionally extract real IPs from headers

Configuration:
- When enabled: Extracts real client IP from X-Forwarded-For header
- When disabled: Uses direct connection IP (default Nginx behavior)
- Supports custom proxy IP ranges for CloudFlare, AWS ALB, etc.

This allows Helmchart to work seamlessly on both:
1. Bare-metal clusters with iptables load balancing
2. Cloud-managed clusters with proper IP forwarding

Version bumped to 6.9.0-a (WordPress version with implementation suffix)

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

templates/deployment.yaml

@@ -68,12 +68,16 @@ spec:
               if (isset($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] === 'https') {
                   $_SERVER['HTTPS'] = 'on';
               }
-              
-              // Add Trusted Proxy (WordPress 5.9+)
+
+              {{- if .Values.nginx.forwardRealIP.enabled }}
+              // Add Trusted Proxy - Extract Real Client IP from X-Forwarded-For header
               if (isset($_SERVER['HTTP_X_FORWARDED_FOR'])) {
                   $forwarded_ips = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
                   $_SERVER['REMOTE_ADDR'] = trim($forwarded_ips[0]);
+              } elseif (isset($_SERVER['HTTP_X_REAL_IP'])) {
+                  $_SERVER['REMOTE_ADDR'] = $_SERVER['HTTP_X_REAL_IP'];
               }
+              {{- end }}
 
               $protocol = 'http';
               if ( isset($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] === 'https' ) {