feat: devshells, formatting, zoxide

devshells/ocaml/flake.nix

@@ -0,0 +1,33 @@
+{
+  description = "OCaml nix-flake devshell.";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-25.11";
+  };
+
+  outputs =
+    { self, nixpkgs, ... }:
+    let
+      system = "x86_64-linux";
+    in
+    {
+      devShells."${system}".default =
+        let
+          pkgs = import nixpkgs {
+            inherit system;
+          };
+        in
+        pkgs.mkShell {
+          packages =
+            with pkgs;
+            with ocamlPackages;
+            [
+              findlib
+              ocaml
+              ocaml-lsp
+              ocamlformat
+              dune_3
+            ];
+        };
+    };
+}