Peekdown turns Quick Look into Markdown previewer

This is a tightly scoped utility that solves an annoying, real workflow gap for people who live in Finder and write in Markdown. The pitch is strong because it is not trying to replace a full editor; it makes Quick Look actually useful for docs, READMEs, and vault files.

• –The main value is immediate preview fidelity: GitHub-style rendering in Finder is the core feature, not a bonus.
• –Obsidian support broadens it beyond plain `.md` files into a real knowledge-base workflow.
• –Copyable code blocks and inline editing make it more than a passive viewer.
• –The one-time purchase model fits the kind of utility this is.