chore(nix): trigger vendorHash recalculation

Setting vendorHash to placeholder to trigger CI failure with correct hash.
Go dependencies were updated.

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

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

default.nix

@@ -9,7 +9,7 @@ pkgs.buildGoModule {
   subPackages = [ "cmd/bd" ];
   doCheck = false;
   # Go module dependencies hash (computed via nix build)
-  vendorHash = "sha256-RJ8LMS2kdKvvkpsL7RcDnSyMfwsGKiMb/qpeLUvXZfA=";
+  vendorHash = "sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=";
 
   # Git is required for tests
   nativeBuildInputs = [ pkgs.git ];