docs: roadmap — Nomarchy distro branding (os-release, ISO boot menu, splash)

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

README.md

@@ -240,3 +240,10 @@ workspaces · `Print` region screenshot.
   boot (v1 `nomarchy-install` is single-disk UEFI — see `pkgs/nomarchy-install`)
 - `hyprlock`/`hypridle`, swayosd, launch-or-focus UX scripts
 - swaync notification center (notify-send currently renders bare)
+- **Distro branding:** replace the NixOS brand with Nomarchy everywhere it
+  surfaces — `system.nixos.distroName`/`distroId` (flows into
+  `/etc/os-release`, the live ISO's boot-menu label and the installed
+  system's systemd-boot entries), `isoImage.splashImage`/`grubTheme` for
+  the ISO boot screen, tuigreet/MOTD text. Caveats: `distroId` also
+  changes `DEFAULT_HOSTNAME` and some upstream `isNixos` checks, and
+  nixos-* CLI names stay (renaming tooling is not worth the drift)