feat: initialization migration to Nuxt + Backend

This commit initializes both the Nuxt frontend and the Rust backend of
the new version of phundrak.com

flake.nix

@@ -0,0 +1,50 @@
+{
+  inputs = {
+    nixpkgs.url = "github:cachix/devenv-nixpkgs/rolling";
+    systems.url = "github:nix-systems/default";
+    alejandra = {
+      url = "github:kamadorueda/alejandra/4.0.0";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+    devenv = {
+      url = "github:cachix/devenv";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  nixConfig = {
+    extra-trusted-public-keys = "devenv.cachix.org-1:w1cLUi8dv3hnoSPGAuibQv+f9TZLr6cv/Hm9XgU50cw=";
+    extra-substituters = "https://devenv.cachix.org";
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    devenv,
+    systems,
+    rust-overlay,
+    alejandra,
+    ...
+  } @ inputs: let
+    forEachSystem = nixpkgs.lib.genAttrs (import systems);
+  in {
+    formatter = forEachSystem (system: alejandra.defaultPackage.${system});
+
+    devShells = forEachSystem (
+      system: let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in {
+        backend = import ./backend/shell.nix {
+          inherit inputs pkgs system self rust-overlay;
+        };
+        frontend = import ./frontend/shell.nix {
+          inherit inputs pkgs self;
+        };
+      }
+    );
+  };
+}