Remove invalid LLMs directive from robots.txt

The LLMs: field is not a recognised robots.txt directive and causes
a syntax error in Google Search Console. llms.txt is still served
at its URL and discoverable without being declared here.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: ChengaDev

public/robots.txt

@@ -2,7 +2,6 @@
 User-agent: *
 Allow: /
 Sitemap: https://www.24shotclock.com/sitemap.xml
-LLMs: https://www.24shotclock.com/llms.txt
 
 # AI crawlers
 User-agent: GPTBot