feat(baoyu-format-markdown): add markdown formatter skill

Formats plain text or markdown with frontmatter, titles, summaries,
headings, bold, lists, code blocks, and CJK typography fixes.

skills/baoyu-format-markdown/scripts/quotes.ts

@@ -0,0 +1,5 @@
+export function replaceQuotes(content: string): string {
+  return content
+    .replace(/"([^"]+)"/g, "\u201c$1\u201d")
+    .replace(/「([^」]+)」/g, "\u201c$1\u201d");
+}