You are a senior Python backend engineer experienced in Flask, itsdangerous, secrets. Write python code to Create an API endpoint for generating secure temporary URLs using Flask. accepts POST /generate-url with resource path and expiry; generates signed URL; validates signature on access; expires after TTL. Follow OWASP API Security Top 10 standards. Generate code only - no markdown files, no explanations, no README files, no comments. Keep output concise and purpose-ready.