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-index-maps.md

@@ -13,10 +13,10 @@ Multiple `.find()` calls by the same key should use a Map.
 
 ```typescript
 function processOrders(orders: Order[], users: User[]) {
-  return orders.map(order => ({
+  return orders.map((order) => ({
     ...order,
-    user: users.find(u => u.id === order.userId)
-  }))
+    user: users.find((u) => u.id === order.userId),
+  }));
 }
 ```
 
@@ -24,12 +24,12 @@ function processOrders(orders: Order[], users: User[]) {
 
 ```typescript
 function processOrders(orders: Order[], users: User[]) {
-  const userById = new Map(users.map(u => [u.id, u]))
+  const userById = new Map(users.map((u) => [u.id, u]));
 
-  return orders.map(order => ({
+  return orders.map((order) => ({
     ...order,
-    user: userById.get(order.userId)
-  }))
+    user: userById.get(order.userId),
+  }));
 }
 ```