🛡️ Sentinel: [CRITICAL] Fix hardcoded secret and unconditionally block XML-RPC

[Snider]

🚨 Severity: CRITICAL
💡 Vulnerability: A hardcoded token (xrpc-9f8e7d6c5b4a) was found in wordpress.conf, which acted as a backdoor to bypass the intended block on /xmlrpc.php. Additionally, the Nginx version was being broadcasted.
🎯 Impact: An attacker who discovered the token could access the WordPress XML-RPC endpoint, facilitating brute-force attacks, DDoS amplification, and potential remote code execution depending on the WordPress version and plugins. Leaking the Nginx version aids attackers in identifying known vulnerabilities for that specific version.
🔧 Fix:

1. Replaced the conditional bypass with an unconditional deny all; for /xmlrpc.php, while turning off access_log and log_not_found.
2. Added server_tokens off; to nginx.conf, unified.conf, wordpress.conf, and linuxkit.yml to suppress the Nginx server version in responses.
   ✅ Verification: Verified Nginx configuration syntax using nginx -t. Reviewed all modified configurations to ensure correct application of directives. Extraneous test files were cleaned up.

---

PR created automatically by Jules for task 8864962518008518134 started by @Snider

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.