docs: add star history chart to README

Author: iamtoruk

README.md

@@ -328,6 +328,16 @@ src/
     pi.ts         Pi agent JSONL session discovery and parsing
 ```
 
+## Star History
+
+<a href="https://www.star-history.com/?repos=getagentseal%2Fcodeburn&type=date&legend=top-left">
+ <picture>
+   <source media="(prefers-color-scheme: dark)" srcset="https://api.star-history.com/chart?repos=getagentseal/codeburn&type=date&theme=dark&legend=top-left" />
+   <source media="(prefers-color-scheme: light)" srcset="https://api.star-history.com/chart?repos=getagentseal/codeburn&type=date&legend=top-left" />
+   <img alt="Star History Chart" src="https://api.star-history.com/chart?repos=getagentseal/codeburn&type=date&legend=top-left" />
+ </picture>
+</a>
+
 ## License
 
 MIT