Add a basic nix flake for development (#6531)

* feat: add a basic nix flake

* fix: dev server on nixos

.gitignore

@@ -16,3 +16,8 @@ config.json
 # vim
 *.sw?
 
+# direnv
+.direnv/
+
+# environment related
+.envrc

flake.lock

@@ -0,0 +1,60 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1739874174,
+        "narHash": "sha256-XGxSVtojlwjYRYGvGXex0Cw+/363EVJlbY9TPX9bARk=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "d2ab2691c798f6b633be91d74b1626980ddaff30",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,34 @@
+{
+  description = "jellyfin-web nix flake";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    flake-utils,
+  }:
+    flake-utils.lib.eachDefaultSystem (
+      system: let
+        pkgs = import nixpkgs {
+          inherit system;
+        };
+      in {
+        devShell = with pkgs;
+          mkShell rec {
+            buildInputs = [
+              nodejs_20
+            ];
+
+            shellHook = ''
+              # Also see: https://github.com/sass/embedded-host-node/issues/334
+              echo "Removing sass-embedded from node-modules as its broken on NixOS."
+              rm -rf node_modules/sass-embedded*
+            '';
+          };
+      }
+    );
+}