chore: add treefmt

cells/repo/devShells.nix

@@ -1,8 +1,16 @@
 {inputs, ...}: let
-  inherit (inputs) pkgs dslib;
+  inherit (inputs) pkgs dslib treefmt;
 in {
   default = dslib.mkShell {
-    packages = [pkgs.alejandra];
+    packages = [
+      (treefmt.mkWrapper pkgs {
+        programs = {
+          alejandra.enable = true;
+          mdformat.enable = true;
+        };
+        settings.global.excludes = ["*LICENSE*.md"];
+      })
+    ];
     enterShellCommands."ren".text = "echo Hello rensa!";
   };
 }

cells/repo/flake.lock

@@ -37,7 +37,24 @@
     "root": {
       "inputs": {
         "devshell": "devshell",
-        "nixmkdocs": "nixmkdocs"
+        "nixmkdocs": "nixmkdocs",
+        "treefmt-nix": "treefmt-nix"
+      }
+    },
+    "treefmt-nix": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1755934250,
+        "narHash": "sha256-CsDojnMgYsfshQw3t4zjRUkmMmUdZGthl16bXVWgRYU=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "74e1a52d5bd9430312f8d1b8b0354c92c17453e5",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
       }
     }
   },

cells/repo/flake.nix

@@ -2,6 +2,10 @@
   inputs = {
     devshell.url = "gitlab:rensa-nix/devshell?dir=lib";
     nixmkdocs.url = "gitlab:TECHNOFAB/nixmkdocs?dir=lib";
+    treefmt-nix = {
+      url = "github:numtide/treefmt-nix";
+      flake = false;
+    };
   };
 
   outputs = i:
@@ -9,5 +13,6 @@
     // {
       dslib = i.devshell.lib {inherit (i.parent) pkgs;};
       doclib = i.nixmkdocs.lib {inherit (i.parent) pkgs;};
+      treefmt = import i.treefmt-nix;
     };
 }