fix: resolve Prettier markdown code block parsing errors

- Fix syntax errors in skills markdown files (.github/skills, .opencode/skills)
- Change typescript to tsx for code blocks with JSX
- Replace ellipsis (...) in array examples with valid syntax
- Separate CSS from TypeScript into distinct code blocks
- Convert JavaScript object examples to valid JSON in docs
- Fix enum definitions with proper comma separation

.opencode/skills/vercel-react-best-practices/rules/rendering-activity.md

@@ -12,14 +12,14 @@ Use React's `<Activity>` to preserve state/DOM for expensive components that fre
 **Usage:**
 
 ```tsx
-import { Activity } from 'react'
+import { Activity } from "react";
 
 function Dropdown({ isOpen }: Props) {
   return (
-    <Activity mode={isOpen ? 'visible' : 'hidden'}>
+    <Activity mode={isOpen ? "visible" : "hidden"}>
       <ExpensiveMenu />
     </Activity>
-  )
+  );
 }
 ```