mindX Publish Auth 0.1.0

Initial public release.

• 4 REST endpoints under /wp-json/mindx/v1/ (challenge, verify, whoami, diagnose)
• Pure-PHP secp256k1 ECDSA recovery + Keccak-256
• 32-byte HS256 JWT secret generated on activation, rotatable from admin
• Ring-buffer audit log

See docs/ for the protocol, security model, and install guide.