Add application screenshot to README

Shows Runway's week view with events, all-day events, and dark theme

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

README.md

@@ -1,6 +1,8 @@
 # Runway
 ## _Passive infrastructure for life's coordination_
 
+![Runway Screenshot](sample.png)
+
 >[!WARNING]
 >This project was entirely vibe coded. It's my first attempt vibe coding anything, but I just sat down one day and realized this was something I've wanted to build for many years, but would just take way too long. With AI, I've been able to lay out the majority  of the app in one long weekend. So proceed at your own risk, but I actually think the app is pretty solid.