docs: Add guide for using skills in AgentSkills/Claude format

overview/skills.mdx

@@ -5,6 +5,10 @@ description: Skills are specialized prompts that enhance OpenHands with domain-s
 
 Skills are specialized prompts that enhance OpenHands with domain-specific knowledge, expert guidance, and automated task handling. They provide consistent practices across projects and can be triggered automatically based on keywords or context.
 
+<Info>
+OpenHands supports an **extended version** of the [AgentSkills standard](https://agentskills.io/specification) with optional keyword triggers for automatic activation. See the [SDK Skills Guide](/sdk/guides/skill) for details on the SKILL.md format.
+</Info>
+
 ## Official Skill Registry
 
 The official global skill registry is maintained at [github.com/OpenHands/skills](https://github.com/OpenHands/skills). This repository contains community-shared skills that can be used by all OpenHands agents. You can browse available skills, contribute your own, and learn from examples created by the community.