docs: add ccusage Raycast Extension to Related Projects

Add the ccusage Raycast Extension to the Related Projects section, which provides a convenient way to view Claude Code usage reports directly within Raycast.

Author: nyatinte

README.md

@@ -500,6 +500,7 @@ While the original approach uses DuckDB for analysis, this tool provides a more
 some projects use `ccusage` internally and provide additional features:
 
 - [claude-usage-tracker-for-mac](https://github.com/penicillin0/claude-usage-tracker-for-mac) – macOS menu bar app to visualize Claude Code usage costs by [@penicillin0](https://github.com/penicillin0).
+- [ccusage Raycast Extension](https://www.raycast.com/nyatinte/ccusage) – Raycast extension to view Claude Code usage reports in Raycast by [@nyatinte](https://github.com/nyatinte).
 
 ## Acknowledgments