logiguard fork: GPUI xdg-activation keyboard-focus serial fix

Single-commit orphan branch: full zed-industries/zed @ 8c74db0 source tree
with a 3-file patch applied (no upstream history).

Patch (crates/gpui_linux/src/linux/wayland/):
  - serial.rs: add SerialKind::KeyboardEnter
  - client.rs: store wl_keyboard.enter serial; add latest_serial_of()
  - window.rs: activate() uses keyboard-enter serial (Mutter focus gate)

Mutter honors window activation only when the token carries the keyboard-
focus serial from wl_keyboard.enter; GPUI used a stale mouse-press serial.
See docs/tray-window-focus-wayland.md in logiguard.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

nix/modules/devshells.nix

@@ -0,0 +1,79 @@
+{ inputs, ... }:
+{
+  perSystem =
+    { pkgs, ... }:
+    let
+      # NOTE: Duplicated because this is in a separate flake-parts partition
+      # than ./packages.nix
+      mkZed = import ../toolchain.nix { inherit inputs; };
+      zed-editor = mkZed pkgs;
+
+      rustBin = inputs.rust-overlay.lib.mkRustBin { } pkgs;
+      rustToolchain = rustBin.fromRustupToolchainFile ../../rust-toolchain.toml;
+
+      baseEnv =
+        (zed-editor.overrideAttrs (attrs: {
+          passthru.env = attrs.env;
+        })).env; # exfil `env`; it's not in drvAttrs
+
+      # Musl cross-compiler for building remote_server
+      muslCross = pkgs.pkgsCross.musl64;
+
+      # Cargo build timings wrapper script
+      wrappedCargo = pkgs.writeShellApplication {
+        name = "cargo";
+        runtimeInputs = [ pkgs.nodejs ];
+        text =
+          let
+            pathToCargoScript = ./. + "/../../script/cargo";
+          in
+          ''
+            NIX_WRAPPER=1 CARGO=${rustToolchain}/bin/cargo ${pathToCargoScript} "$@"
+          '';
+      };
+    in
+    {
+      devShells.default = (pkgs.mkShell.override { inherit (zed-editor) stdenv; }) {
+        name = "zed-editor-dev";
+        inputsFrom = [ zed-editor ];
+
+        packages = with pkgs; [
+          wrappedCargo # must be first, to shadow the `cargo` provided by `rustToolchain`
+          rustToolchain # cargo, rustc, and rust-toolchain.toml components included
+          cargo-nextest
+          cargo-hakari
+          cargo-machete
+          cargo-zigbuild
+          # TODO: package protobuf-language-server for editing zed.proto
+          # TODO: add other tools used in our scripts
+
+          # `build.nix` adds this to the `zed-editor` wrapper (see `postFixup`)
+          # we'll just put it on `$PATH`:
+          nodejs_22
+          zig
+        ];
+
+        env =
+          (removeAttrs baseEnv [
+            "LK_CUSTOM_WEBRTC" # download the staticlib during the build as usual
+            "ZED_UPDATE_EXPLANATION" # allow auto-updates
+            "CARGO_PROFILE" # let you specify the profile
+            "TARGET_DIR"
+          ])
+          // {
+            # note: different than `$FONTCONFIG_FILE` in `build.nix` – this refers to relative paths
+            # outside the nix store instead of to `$src`
+            FONTCONFIG_FILE = pkgs.makeFontsConf {
+              fontDirectories = [
+                "./assets/fonts/lilex"
+                "./assets/fonts/ibm-plex-sans"
+              ];
+            };
+            PROTOC = "${pkgs.protobuf}/bin/protoc";
+            ZED_ZSTD_MUSL_LIB = "${pkgs.pkgsCross.musl64.pkgsStatic.zstd.out}/lib";
+            # For aws-lc-sys musl cross-compilation
+            CC_x86_64_unknown_linux_musl = "${muslCross.stdenv.cc}/bin/x86_64-unknown-linux-musl-gcc";
+          };
+      };
+    };
+}