feat: Add manual testing of bindings with Valgrind

(cherry picked from commit 12fed067bf230d3258db172afe648ec690ba584c)

flake.nix

@@ -55,6 +55,11 @@
               pkgs.rustfmt
               pkgs.pkg-config
               pkgs.clang-tools # clangd
+              pkgs.valgrind
+              # TODO: set up cargo-valgrind in shell and build
+              #       currently both this and `cargo install cargo-valgrind`
+              #       produce a binary that says ENOENT.
+              # pkgs.cargo-valgrind
             ];
             shellHook = ''
               ${config.pre-commit.installationScript}