feat(cli): add settings support for experimental skills

- Add tools.experimentalSkills setting in settingsSchema
- Read default from settings in config. ts
- Add --skills as shorter alias for --experimental-skills
- Update documentation for new setting

Fixes #1493

docs/users/features/skills.md

@@ -11,10 +11,29 @@ This guide shows you how to create, use, and manage Agent Skills in **Qwen Code*
 ## Prerequisites
 
 - Qwen Code (recent version)
-- Run with the experimental flag enabled:
+
+## How to enable
+
+### Via CLI flag
 
 ```bash
+# Long form
 qwen --experimental-skills
+
+# Short form
+qwen --skills
+```
+
+### Via settings.json
+
+Add to your `~/.qwen/settings.json` or project's `.qwen/settings.json`:
+
+```json
+{
+  "tools": {
+    "experimentalSkills": true
+  }
+}
 ```
 
 - Basic familiarity with Qwen Code ([Quickstart](../quickstart.md))