Create llms-txt-validation.js

Fetches /llms.txt and returns a simple validity flag (1 or 0). It checks that the response:

- Succeeds (HTTP 2xx)
- Has a Content-Type of text/plain
- Contains balanced Markdown code fences (…)
- Has matching counts of [ vs. ] and ( vs. )

If any check fails, it returns 0; otherwise it returns 1.

Author: chr156r33n

llms-txt-validation.js

@@ -0,0 +1,14 @@
+[llms-txt-valid]
+return fetch('/llms.txt')
+  .then(response => {
+    if (!response.ok) return 0;
+    const ct = response.headers.get('Content-Type')||'';
+    if (!ct.toLowerCase().includes('text/plain')) return 0;
+    return response.text().then(text => {
+      const m = s=> (text.match(new RegExp(`\\${s}`,'g'))||[]).length;
+      if ((text.match(/```/g)||[]).length %2) return 0;
+      if (m('[')!==m(']')||m('(')!==m(')')) return 0;
+      return 1;
+    });
+  })
+  .catch(()=>0);