+beads + opencode overlays

overlays/mods/default.nix

@@ -3,6 +3,8 @@
   # This overlay contains package overrides and modifications
 
   n8n = import ./n8n.nix {inherit prev;};
+  opencode = import ./opencode.nix {inherit prev;};
+  beads = import ./beads.nix {inherit prev;};
 
   # Add more modifications here as needed
   # example-package = prev.example-package.override { ... };