[agentic-payment-service/skill/bot/assistant] Added an article covering all 13 categories of secrets management approaches, plus a comparison matrix and architectural recommendations for different scales. It is covering and includes - local encryption, OS keyrings, HSMs, TPMs, smart cards, cloud KMS, self-hosted and SaaS platforms, CI/CD native stores, IaC tools, threshold/MPC systems, injection tools, and detection/leak prevention.

Author: andrcmdr