wrapped frontmatter description in single quotes per guidelines

Author: nickytonline

instructions/tanstack-start-shadcn-tailwind.md

@@ -1,5 +1,5 @@
 ---
-description: Guidelines for building TanStack Start applications
+description: 'Guidelines for building TanStack Start applications'
 ---
 
 # TanStack Start with Shadcn/ui Development Guide
@@ -208,4 +208,4 @@ npx shadcn@latest add button card input dialog
 - Include error/pending boundaries on all routes
 - Prefer Shadcn components over custom UI
 - Use `@/` imports consistently
-- Follow accessibility best practices
+- Follow accessibility best practices