docs: put the install command first on the site entry point

The page opened with git clone, while the repository's primary install path is npx skills add; a visitor landing on the site had to open the README to find the one command that installs the skill.

Author: angel291592

docs/index.md

@@ -34,6 +34,12 @@ question by looking it up or asking, then **Typecheck and emit** — route, ask,
 
 ## Get it
 
+```bash
+npx skills add angel291592/Intent-Router
+```
+
+Or clone it and copy `skills/intent-router/` into your harness's skills directory:
+
 ```bash
 git clone https://github.com/angel291592/Intent-Router.git
 ```