chore: add nix flake

flake.nix

@@ -0,0 +1,44 @@
+{
+  description = "A very basic flake";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+  };
+
+  outputs = { self, nixpkgs }: 
+    let
+      system = "x86_64-linux";
+
+      pkgs = import nixpkgs {
+        inherit system;
+        config = {
+          allowUnfree = true;
+          android_sdk.accept_license = true;
+        };
+      };
+
+      androidComposition = pkgs.androidenv.composeAndroidPackages {
+        platformVersions = [ "31" "33" "34" ];
+        buildToolsVersions = [ "34.0.0" ];
+        includeNDK = true;
+        includeEmulator = true;
+        includeSystemImages = true;
+      };
+
+      androidSdk = androidComposition.androidsdk;
+    in {
+
+      devShell.${system} = pkgs.mkShell {
+        packages = with pkgs; [
+          flutter
+          jdk17
+          androidSdk
+        ];
+
+        shellHook = ''
+          export ANDROID_HOME="${androidSdk}/libexec/android-sdk"
+          export JAVA_HOME="${pkgs.jdk17}"
+        '';
+      };
+    };
+}