v0.4.3 -- Rich Substack reader

• Render Substack post bodies as rich HTML (images, links, formatting, blockquotes, code blocks)
• Clickable links open in default browser
• Larger save/dismiss hover buttons on collapsed posts
• Fira Sans / Fira Code fonts in post reader to match app style
• Scroll passthrough so WebView doesn't trap scroll events

Full Changelog: v0.4.2...v0.4.3