logiguard fork v3: full patch set on verified 8c74db0 tree

Includes prior-session patches (carry forward so the app compiles):
  - crates/gpui/build.rs: cross-compile manifest fix
  - crates/gpui/src/platform.rs: PlatformWindow::activate_with_token trait method
  - crates/gpui/src/window.rs: Window::activate_with_token public API
  - crates/gpui_linux/src/linux/wayland/window.rs: WaylandWindow::activate_with_token + activate() keyboard-serial fix

Plus the focus-serial fix:
  - serial.rs: SerialKind::KeyboardEnter
  - client.rs: store wl_keyboard.enter serial; latest_serial_of()

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

nix/modules/treefmt.nix

@@ -0,0 +1,10 @@
+{
+  perSystem =
+    { pkgs, ... }:
+    {
+      treefmt = {
+        programs.nixfmt.enable = true;
+        programs.rustfmt.enable = true;
+      };
+    };
+}