🔒️ annual upgrade

- also bumped tailwind to 4.x
- updated postcss to match

flake.nix

@@ -2,7 +2,7 @@
   description = "walkah.net";
 
   inputs = {
-    nixpkgs.url = "github:nixos/nixpkgs/nixos-23.11";
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-25.05";
     flake-utils.url = "github:numtide/flake-utils";
 
     flake-compat = {
@@ -11,23 +11,29 @@
     };
   };
 
-  outputs = { nixpkgs, flake-utils, ... }:
-    flake-utils.lib.eachDefaultSystem
-      (system:
-        let pkgs = nixpkgs.legacyPackages.${system};
-        in
-        {
-          devShells.default = pkgs.mkShell {
-            name = "net";
-            buildInputs = with pkgs; [ libyaml nodejs ruby ];
-            shellHook = ''
-              mkdir -p .gems
+  outputs =
+    { nixpkgs, flake-utils, ... }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          name = "net";
+          buildInputs = with pkgs; [
+            libyaml
+            nodejs
+            ruby
+          ];
+          shellHook = ''
+            mkdir -p .gems
 
-              export GEM_HOME=$PWD/.gems
-              export GEM_PATH=$GEM_HOME
-              export PATH=$PWD/bin:$GEM_HOME/bin:$PATH
-            '';
-          };
-        }
-      );
+            export GEM_HOME=$PWD/.gems
+            export GEM_PATH=$GEM_HOME
+            export PATH=$PWD/bin:$GEM_HOME/bin:$PATH
+          '';
+        };
+      }
+    );
 }