add flake.nix with an mrvc package for various platforms

Only tested x86_64-linux, but the other platforms should just work as
well.

.gitignore

@@ -0,0 +1 @@
+/result

flake.lock

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+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1755471983,
+        "narHash": "sha256-axUoWcm4cNQ36jOlnkD9D40LTfSQgk8ExfHSRm3rTtg=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "48f4c982de68d966421d2b6f1ddbeb6227cc5ceb",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-25.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

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+{
+  description = "mrvc (max room version checker) - a tool for determining how many members support which maximum room version for a given Matrix room";
+
+  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-25.05";
+
+  outputs = { nixpkgs, ... }: {
+    packages = nixpkgs.lib.attrsets.genAttrs [ "x86_64-linux" "aarch64-linux" "i686-linux" "x86_64-darwin" "aarch64-darwin" ] (system:
+      let
+        pkgs = nixpkgs.legacyPackages."${system}";
+        lib = nixpkgs.lib;
+      in
+      rec {
+        mrvc = pkgs.buildGoModule (finalAttrs: {
+          pname = "mrvc";
+          version = "0.0.1";
+
+          src = ./.;
+
+          vendorHash = "sha256-aIPSQSAgsCOL5BR0u28XSO98GY9/5Auvs6tJFy3O7gU=";
+
+          meta = {
+            description = "mrvc - (Matrix) max room version checker";
+            longDescription = "A tool for determining how many members support which maximum room version for a given Matrix room.";
+            homepage = "https://codeberg.org/june64/mrvc";
+            license = lib.licenses.mit;
+          };
+        });
+        default = mrvc;
+      }
+    );
+  };
+}