[Feature] TLS termination and security hardening

[ElioNeto]

Overview

Implement TLS termination in the Go Core and harden all security mechanisms described in the spec.

Acceptance Criteria

• Core manages TLS certificates and terminates HTTPS (HTTP/1.1 and HTTP/2)
• Support for automatic certificate renewal (Let's Encrypt / ACME)
• Header sanitization applied to all incoming requests
• Workers run under restricted filesystem access (configurable)
• Rate limiting enforced per IP and per token (configurable limits in vyx.yaml)
• Global request timeout and maximum payload size limits
• All access attempts logged with: timestamp, route, user, status

References

• Spec §7 – Security
• Roadmap – Phase 3