chore: add Quartus Prime Lite toolchain via nix flake in devbox

nix/flake.nix

@@ -0,0 +1,21 @@
+{
+  description = "STRIX FPGA toolchain";
+
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+
+  outputs = { nixpkgs, ... }:
+    let
+      # Quartus is unfree (free of charge, proprietary) and only built for x86_64-linux.
+      pkgs = import nixpkgs {
+        system = "x86_64-linux";
+        config.allowUnfree = true;
+      };
+    in
+    {
+      # Only the Vidor's FPGA family; Questa is dropped in favour of open-source simulators.
+      packages.x86_64-linux.quartus = pkgs.quartus-prime-lite.override {
+        supportedDevices = [ "Cyclone 10 LP" ];
+        withQuesta = false;
+      };
+    };
+}