ci: nix flake

.envrc

@@ -0,0 +1 @@
+use flake

flake.lock

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+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1753399495,
+        "narHash": "sha256-7XG/QBqhrYOyA2houjRTL2NMa7IKZZ/somBqr+Q/6Wo=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "0d00f23f023b7215b3f1035adb5247c8ec180dbc",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,24 @@
+{
+  description = "devshell";
+
+  outputs =
+    { nixpkgs, ... }:
+    let
+      forAllSystems =
+        f: nixpkgs.lib.genAttrs nixpkgs.lib.systems.flakeExposed (s: f nixpkgs.legacyPackages.${s});
+    in
+    {
+      devShells = forAllSystems (pkgs: {
+        default = pkgs.mkShell {
+          packages = with pkgs; [
+            stdenv.cc.cc
+            arduino-cli
+            platformio
+          ];
+
+          LD_LIBRARY_PATH = "${pkgs.stdenv.cc.cc.lib}/lib";
+          ARDUINO_CONFIG_FILE = "./arduino-cli.yaml";
+        };
+      });
+    };
+}