feat: enhance Apache config for Traefik reverse proxy

- Add RemoteIP configuration to capture real client IPs
- Enable HTTPS detection via X-Forwarded-Proto header
- Add security headers (X-Frame-Options, CSP, etc.)
- Disable Apache WebDAV to prevent conflicts with Nextcloud
- Add module activation script for remoteip and env
- Optimize Directory options (FollowSymLinks without MultiViews)
- Add commented alternative PHP limits for reference

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

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

apache/enable-modules.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+# Active les modules Apache nécessaires pour Nextcloud derrière Traefik
+
+a2enmod remoteip   # Pour récupérer les vraies IPs clients
+a2enmod env        # Pour SetEnvIf (détection HTTPS)
+
+# Redémarre Apache
+apache2ctl graceful