fix(nix): resolve deprecation warnings and document flake usage

- Replace deprecated `import nixpkgs { inherit system; }` with
  `localSystem` to silence 'system' deprecation warning
- Use `stdenv.hostPlatform.isDarwin/isLinux` instead of the deprecated
  `stdenv.isDarwin/isLinux`
- Replace deprecated `xorg.libX*` with top-level `libx*` package names
- Remove deprecated `mesa.drivers` (already covered by `mesa`)
- Reset pnpmDeps hash to empty — consumers using a different nixpkgs
  channel need to override it anyway, and this avoids hash drift on
  every pnpm-lock.yaml update
- Add NixOS/Nix flake installation section to README with override
  instructions for the pnpmDeps hash

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ratierd

README.md

@@ -64,6 +64,39 @@ Connect to remote machines via SSH/SFTP to work with remote codebases. Emdash su
 - AppImage (x64): https://github.com/generalaction/emdash/releases/latest/download/emdash-x86_64.AppImage
 - Debian package (x64): https://github.com/generalaction/emdash/releases/latest/download/emdash-amd64.deb
 
+### NixOS / Nix Flake
+
+This repository exposes a Nix flake with `packages.<system>.emdash`. You can run it directly:
+
+```bash
+nix run github:generalaction/emdash
+```
+
+To install it as part of a NixOS or home-manager configuration, add the flake input and use the package:
+
+```nix
+# flake.nix
+{
+  inputs.emdash.url = "github:generalaction/emdash";
+
+  # ... in your outputs:
+  # packages = [ inputs.emdash.packages.${system}.default ];
+}
+```
+
+> **Note:** The `pnpmDeps` hash is pinned against the flake's own nixpkgs. If you
+> override `emdash.inputs.nixpkgs.follows` to a different nixpkgs, the pnpm version
+> may differ and produce a hash mismatch. In that case, run `nix build` once — Nix
+> will print the correct hash in the error — then apply it:
+>
+> ```nix
+> inputs.emdash.packages.${pkgs.system}.default.overrideAttrs (old: {
+>   pnpmDeps = old.pnpmDeps.overrideAttrs {
+>     outputHash = "<hash from error>";
+>   };
+> });
+> ```
+
 ### Release Overview
 
 **[Latest Releases (macOS • Windows • Linux)](https://github.com/generalaction/emdash/releases/latest)**

flake.nix

@@ -9,7 +9,7 @@
   outputs = { self, nixpkgs, flake-utils, ... }:
     flake-utils.lib.eachDefaultSystem (system:
       let
-        pkgs = import nixpkgs { inherit system; };
+        pkgs = import nixpkgs { localSystem = system; };
         lib = pkgs.lib;
         packageJson = builtins.fromJSON (builtins.readFile ./package.json);
         pnpmPackageManager = packageJson.packageManager or "";
@@ -84,10 +84,10 @@
             pkgs.automake
             pkgs.coreutils
           ]
-          ++ lib.optionals pkgs.stdenv.isDarwin [
+          ++ lib.optionals pkgs.stdenv.hostPlatform.isDarwin [
             pkgs.libiconv
           ]
-          ++ lib.optionals pkgs.stdenv.isLinux [
+          ++ lib.optionals pkgs.stdenv.hostPlatform.isLinux [
             pkgs.libsecret
             pkgs.sqlite
             pkgs.zlib
@@ -96,7 +96,7 @@
           ];
         cleanSrc = lib.cleanSource ./.;
         emdashPackage =
-          if pkgs.stdenv.isLinux then
+          if pkgs.stdenv.hostPlatform.isLinux then
             pkgs.stdenv.mkDerivation rec {
               pname = "emdash";
               version = packageJson.version;
@@ -144,16 +144,15 @@
                 pkgs.libdrm
                 pkgs.pango
                 pkgs.cairo
-                pkgs.xorg.libX11
-                pkgs.xorg.libXcomposite
-                pkgs.xorg.libXdamage
-                pkgs.xorg.libXext
-                pkgs.xorg.libXfixes
-                pkgs.xorg.libXrandr
-                pkgs.xorg.libxcb
+                pkgs.libx11
+                pkgs.libxcomposite
+                pkgs.libxdamage
+                pkgs.libxext
+                pkgs.libxfixes
+                pkgs.libxrandr
+                pkgs.libxcb
                 pkgs.libxkbcommon
                 pkgs.expat
-                pkgs.mesa.drivers
               ];
               env = {
                 HOME = "$TMPDIR/emdash-home";