chore(audit): delete NixOS-irrelevant Omarchy port scripts

Pillar 3 Phase B, batch 2. Five `unused?` scripts that either duplicate
NixOS-native facilities or reference infrastructure Nomarchy doesn't
ship. All five had no callers anywhere in the tree.

- `nomarchy-rollback`: ran `nixos-rebuild rollback` after listing
  `snapper` snapshots. NixOS already exposes the previous generation in
  the boot menu and `nixos-rebuild --rollback`; Nomarchy uses
  impermanence, not snapper.
- `nomarchy-snapshot`: wrapped `snapper create/restore`. Same reason —
  snapper isn't part of Nomarchy. The script's "nomarchy-update can use
  this" comment never came true; nomarchy-update has no reference to it.
- `nomarchy-migrate-state`: one-time migration from old
  `~/.config/home-manager/state.json` and `/etc/nixos/state.json` to the
  unified `~/.config/nomarchy/state.json`. The installer now seeds the
  unified file directly; no current install needs the migration.
- `nomarchy-config-direct-boot`: added an EFI boot entry for a Nomarchy
  UKI. We don't build a UKI (no references anywhere in `core/` or
  `hosts/`), so the script targeted nonexistent infrastructure.
- `nomarchy-npx-install`: generated npx wrappers in `~/.local/bin/`. An
  Arch idiom — on NixOS the path is `nix-shell -p nodejs` or a
  declarative `home.packages` entry.

Kept `nomarchy-build-iso` and `nomarchy-build-live-iso` (the user-flagged
useful build wrappers) and surfaced them in README §2 in place of the
raw `nix build` command, which both removes the audit's `unused?` flag
on them and shortens the docs.

Regenerated docs/SCRIPTS.md (171 → 166 scripts; 28 `unused?` → 21).
Logged in docs/ROADMAP.md Shipped.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

README.md

@@ -40,7 +40,8 @@ This builds a full graphical VM of the installer environment. Once inside, click
 ### 2. Build the Installer ISO
 To install on physical hardware, generate your own bootable image:
 ```bash
-nix build .#nixosConfigurations.nomarchy-installer.config.system.build.isoImage
+./features/scripts/utils/nomarchy-build-iso       # Minimal TTY installer
+./features/scripts/utils/nomarchy-build-live-iso  # Graphical try-before-install
 ```
 The ISO will be located at `./result/iso/nixos-*.iso`. Flash it to a USB drive and boot.