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/js-tosorted-immutable.md

@@ -11,27 +11,21 @@ tags: javascript, arrays, immutability, react, state, mutation
 
 **Incorrect (mutates original array):**
 
-```typescript
+```tsx
 function UserList({ users }: { users: User[] }) {
   // Mutates the users prop array!
-  const sorted = useMemo(
-    () => users.sort((a, b) => a.name.localeCompare(b.name)),
-    [users]
-  )
-  return <div>{sorted.map(renderUser)}</div>
+  const sorted = useMemo(() => users.sort((a, b) => a.name.localeCompare(b.name)), [users]);
+  return <div>{sorted.map(renderUser)}</div>;
 }
 ```
 
 **Correct (creates new array):**
 
-```typescript
+```tsx
 function UserList({ users }: { users: User[] }) {
   // Creates new sorted array, original unchanged
-  const sorted = useMemo(
-    () => users.toSorted((a, b) => a.name.localeCompare(b.name)),
-    [users]
-  )
-  return <div>{sorted.map(renderUser)}</div>
+  const sorted = useMemo(() => users.toSorted((a, b) => a.name.localeCompare(b.name)), [users]);
+  return <div>{sorted.map(renderUser)}</div>;
 }
 ```
 
@@ -46,7 +40,7 @@ function UserList({ users }: { users: User[] }) {
 
 ```typescript
 // Fallback for older browsers
-const sorted = [...items].sort((a, b) => a.value - b.value)
+const sorted = [...items].sort((a, b) => a.value - b.value);
 ```
 
 **Other immutable array methods:**