WIP - add blocks dynamic endpoint with iframe and update sidebar

[sethhorsley]

💅 Blocks got a glow-up (vibed coded but make it work)

Add blocks with preview mode, code mode, AND a fancy file tree sidebar that actually shows you what you're looking at. Revolutionary, I know.

Full disclosure: I vibed coded the HELL out of this, but unlike some AI outputs, I actually know what i am doing lol.

Features that'll make you say "finally"

• ✨ Shiki syntax highlighting - because rainbow code > boring code
• 🌲 Interactive file tree sidebar - with collapsible dirs that ACTUALLY collapse when you click them
• 📁 Proper nested directory support - with correct padding (I measured with a ruler)
• 🔄 Preview/Code tab switching - like you're flipping channels
• 🎯 Smart file highlighting - doesn't ghost you when you switch files
• 🎪 Chevron arrows - that rotate like they're auditioning for Cirque du Soleil

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TL;DR: Blocks are now beautiful, the code preview doesn't lie to you anymore, and everything actually works™. You're welcome.

[georgekettle]

This looks sick! 🚀 @sethhorsley