Add perles TUI package for Beads issue tracking

Adds a custom Nix package for perles, a terminal user interface for the
Beads issue tracking system with BQL query language support.

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/default.nix

@@ -4,4 +4,5 @@
   tea-rbw = pkgs.callPackage ./tea-rbw {};
   app-launcher-server = pkgs.callPackage ./app-launcher-server {};
   claude-code = pkgs.callPackage ./claude-code {};
+  perles = pkgs.callPackage ./perles {};
 }