Markdown Formatter & Beautifier

Markdown pasted from wikis, chats and AI assistants accumulates quirks: #Headings without spaces, * and + and - mixed in one list, three blank lines between paragraphs, trailing spaces everywhere. This formatter tidies all of it in one pass.

The rules are conservative and documented: ATX headings get exactly one space, unordered lists use -, ordered lists keep their numbers, runs of blank lines collapse to one, and fenced code blocks pass through byte-for-byte - your code samples are never reformatted.