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/server-serialization.md

@@ -13,13 +13,13 @@ The React Server/Client boundary serializes all object properties into strings a
 
 ```tsx
 async function Page() {
-  const user = await fetchUser()  // 50 fields
-  return <Profile user={user} />
+  const user = await fetchUser(); // 50 fields
+  return <Profile user={user} />;
 }
 
-'use client'
+('use client');
 function Profile({ user }: { user: User }) {
-  return <div>{user.name}</div>  // uses 1 field
+  return <div>{user.name}</div>; // uses 1 field
 }
 ```
 
@@ -27,12 +27,12 @@ function Profile({ user }: { user: User }) {
 
 ```tsx
 async function Page() {
-  const user = await fetchUser()
-  return <Profile name={user.name} />
+  const user = await fetchUser();
+  return <Profile name={user.name} />;
 }
 
-'use client'
+('use client');
 function Profile({ name }: { name: string }) {
-  return <div>{name}</div>
+  return <div>{name}</div>;
 }
 ```