Run tailwindcss before dx build in flake

flake.nix

@@ -110,6 +110,9 @@
           ] ++ build-pkgs;
 
           buildPhase = ''
+            # dx build will run tailwindcss anyways, but doing it first here is faster and clearer if it fails
+            tailwindcss --input style/tailwind.css --output assets/tailwind.css
+
             dx build --release --frozen --web
           '';