format: apply repo prettier (3.8.1) to the folded skills tree

963 markdown files reformatted with the repository's pinned prettier so
pnpm format:check covers the folded tree like every other repo file.

The formatter's embedded-language pass also normalized code fences
(TS semicolons, closed HTML tags in examples, lowercased CSS hex colors,
one renumbered list that skipped an index). Alphanumeric token deltas vs
the fold commit were audited file-by-file; all are formatter-equivalent
markup normalizations plus the four sanitized skills.

packages/mosaic/framework/skills/vercel-react-best-practices/rules/async-parallel.md

@@ -12,17 +12,13 @@ When async operations have no interdependencies, execute them concurrently using
 **Incorrect (sequential execution, 3 round trips):**
 
 ```typescript
-const user = await fetchUser()
-const posts = await fetchPosts()
-const comments = await fetchComments()
+const user = await fetchUser();
+const posts = await fetchPosts();
+const comments = await fetchComments();
 ```
 
 **Correct (parallel execution, 1 round trip):**
 
 ```typescript
-const [user, posts, comments] = await Promise.all([
-  fetchUser(),
-  fetchPosts(),
-  fetchComments()
-])
+const [user, posts, comments] = await Promise.all([fetchUser(), fetchPosts(), fetchComments()]);
 ```