Remove Arch/nymph path, restore nymph as Void desktop

Delete all Arch-specific files (packages_arch role, profile_desktop_gnome
role, arch.yml group_vars, nymph.yml host_vars, arch dotfiles). Revert
nymph to the void group in inventory, remove the arch play from site.yml,
and restore profile_desktop_host/tasks/nymph.yml to its pre-Arch state
(GRUB + NVIDIA + prime-run). Preserve Void improvements introduced
alongside Arch work (desktop_void_dotfiles, desktop_void_source_tools,
profile_desktop_i3 dir additions, void-specific conditions).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

AGENTS.md

@@ -1,6 +1,6 @@
 # AGENTS.md
 
-Ansible-driven personal infrastructure repo for Void/Arch desktops, Linux workstations, Windows+WSL, and an Ubuntu server.
+Ansible-driven personal infrastructure repo for Void desktops, Linux workstations, Windows+WSL, and an Ubuntu server.
 
 ## Source Of Truth
 - Main orchestration: `ansible/site.yml`
@@ -11,8 +11,7 @@ Ansible-driven personal infrastructure repo for Void/Arch desktops, Linux workst
 - Codex config is rendered from `dotfiles/common/.codex/config.toml.j2` so `model_instructions_file` points to the deployed `~/.config/ai/bootstrap.md`.
 
 ## Topology
-- Void desktops: `ikaros`
-- Arch desktops: `nymph`
+- Void desktops: `ikaros`, `nymph`
 - Native Linux workstations: `deadalus-ubuntu`, `deadalus-fedora`
 - Windows host + WSL dev: `deadalus-win`, `deadalus-wsl`
 - Ubuntu server: `prometheus`
@@ -35,15 +34,13 @@ Ansible-driven personal infrastructure repo for Void/Arch desktops, Linux workst
   - `ansible-lint ansible/roles`
   - `yamllint ansible/`
 - Host-focused dry runs:
-  - Void desktop work: `ansible-playbook ansible/site.yml --limit ikaros --check --diff`
-  - Arch desktop work: `ansible-playbook ansible/site.yml --limit nymph --check --diff`
+  - Void desktop work: `ansible-playbook ansible/site.yml --limit ikaros --check --diff` or `--limit nymph --check --diff`
   - Ubuntu workstation: `ansible-playbook ansible/site.yml --limit deadalus-ubuntu --check --diff`
   - Fedora workstation: `ansible-playbook ansible/site.yml --limit deadalus-fedora --check --diff`
   - WSL dev: `ansible-playbook ansible/site.yml --limit deadalus-wsl --check --diff`
   - Server: `ansible-playbook ansible/site.yml --limit prometheus --check --diff`
 - Focused checks:
   - Emacs dotfiles only: `ansible-playbook ansible/site.yml --limit ikaros --tags emacs --check --diff` or `--limit nymph --tags emacs --check --diff`
-  - Arch GNOME desktop bootstrap on nymph: `ansible-playbook ansible/site.yml --limit nymph --tags packages,services,gnome --check --diff`
   - Mail bootstrap: `sh -n scripts/bootstrap_mail.sh` and `shellcheck scripts/bootstrap_mail.sh`
   - Windows bootstrap parse: `pwsh -NoProfile -Command "[void][System.Management.Automation.Language.Parser]::ParseFile('scripts/bootstrap_windows_workstation.ps1', [ref]$null, [ref]$null)"`
   - Server compose render: `docker compose -f /opt/docker/server/docker-compose.yml config`
@@ -61,15 +58,10 @@ Ansible-driven personal infrastructure repo for Void/Arch desktops, Linux workst
 - `.emacs.d` is deployed by a dedicated `profile_desktop_common` task tagged `emacs`.
 - NTFS filesystem support is provided by `ntfs-3g` in `ansible/inventory/group_vars/void.yml`.
 - Void user services are managed by `turnstile` and live under `dotfiles/desktop/.config/service/`.
-- Arch user services are systemd user units under `dotfiles/desktop/.config/systemd/user/`.
 - `ssh-agent` keeps the stable socket `~/.local/state/ssh-agent/socket`.
 - Critical session entrypoints:
   - `dotfiles/desktop/.xinitrc`
-  - `dotfiles/desktop/.local/bin/start-sway-session`
 - Do not auto-restart `emptty` during playbook runs on active Void desktop hosts; restart it manually from another TTY/SSH session if needed.
-- `nymph` is an Arch GNOME/GDM desktop; do not route it through Void/i3/Sway/emptty tasks.
-- `nymph` uses systemd-boot; keep loader entries and kernel cmdline in `ansible/inventory/host_vars/nymph.yml`.
-- `profile_desktop_sway` owns the Sway session, Noctalia config rendering, and official plugin linking when a Sway desktop is explicitly enabled.
 - Noctalia shared config lives in `dotfiles/desktop/.config/noctalia/`; bar monitors and `screenOverrides` come from inventory (`noctalia_bar_monitors`, `noctalia_screen_overrides`) on Sway hosts.
 - On Sway hosts, `udiskie` is the backend for automount/LUKS but runs without tray; USB device UI is handled by `usb-drive-manager`.
 - Do not re-introduce `network-manager-applet` or `blueman` on Sway hosts without an explicit host-specific reason.