correct content type for all .md files

Author: raymondk

public/.ic-assets.json5

@@ -37,6 +37,17 @@
       "Access-Control-Allow-Headers": "Content-Type"
     }
   },
+  {
+    // User discovery endpoints — SKILL.md files
+    "match": "skills/**/*.md",
+    "headers": {
+      "Content-Type": "text/markdown; charset=utf-8",
+      "Cache-Control": "public, max-age=300, must-revalidate",
+      "Access-Control-Allow-Origin": "*",
+      "Access-Control-Allow-Methods": "GET",
+      "Access-Control-Allow-Headers": "Content-Type"
+    }
+  },
   {
     // Matomo analytics
     "match": "matomo.js",