docs(skills): shorten Rstack skill description

Author: chenjiahan

.agents/skills/rstack-cli-best-practices/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: rstack-cli-best-practices
-description: Guidance for Rstack CLI tasks. Use when running `rs` commands, editing `rstack.config.*`, using `rstack` package imports, or working with Rstack-powered apps, libraries, docs, tests, linting, formatting, Git hooks, staged files, and monorepos. Requires reading the version-matched documentation shipped in the installed `rstack` package before making changes.
+description: Guidance for Rstack CLI work involving `rs` commands, `rstack.config.*`, package APIs, or Rstack-based projects and tooling. Requires reading the version-matched docs bundled with the installed `rstack` package first.
 ---
 
 # Rstack CLI Best Practices