Fix first-run WSL Home Manager activation

[user3301]

Fix the bootstrap error introduced by #17

warning: the following units failed: home-manager-user3301.service
× home-manager-user3301.service - Home Manager environment for user3301
     Loaded: loaded (/etc/systemd/system/home-manager-user3301.service; enabled; preset: ignored)
     Active: failed (Result: exit-code) since Sat 2026-08-15 17:00:12 AEST; 486ms ago
 Invocation: 73c463b401d643438156d2a39fc2ca0c
    Process: 20965 ExecStart=/nix/store/4yzqkkz0ncgjrd936xavhk7jcbwk4asw-hm-setup-env /nix/store/xdgv68mhdl4jdv5233189vx8f0wxdqi1-home-manager-generation (code=exited, status=1/FAILURE)
   Main PID: 20965 (code=exited, status=1/FAILURE)
         IP: 0B in, 0B out
         IO: 4K read, 0B written
   Mem peak: 35.7M
        CPU: 492ms

Aug 15 17:00:12 nixos hm-activate-user3301[20965]: Activating linkGeneration
Aug 15 17:00:12 nixos hm-activate-user3301[20965]: Creating home file links in /home/user3301
Aug 15 17:00:12 nixos hm-activate-user3301[20965]: Activating onFilesChange
Aug 15 17:00:12 nixos hm-activate-user3301[20965]: Activating reloadSystemd
Aug 15 17:00:12 nixos hm-activate-user3301[21228]: Starting units: gpg-agent.socket
Aug 15 17:00:12 nixos hm-activate-user3301[21228]: Error: Error switching systemd units
Aug 15 17:00:12 nixos hm-activate-user3301[21228]: Caused by:
Aug 15 17:00:12 nixos hm-activate-user3301[21228]:     0: Failed to perform post-reload tasks
Aug 15 17:00:12 nixos hm-activate-user3301[21228]:     1: Failed to start unit gpg-agent.socket
Aug 15 17:00:12 nixos hm-activate-user3301[21228]:     2: org.freedesktop.systemd1.NoSuchUnit: Unit gpg-agent.socket not found.
Command 'systemd-run -E LOCALE_ARCHIVE -E NIXOS_INSTALL_BOOTLOADER -E NIXOS_NO_CHECK --collect --no-ask-password --pipe --quiet --service-type=exec --unit=nixos-rebuild-switch-to-configuration /nix/store/p7k7y2xkxm9gbxdm4pp7k036k9mf9jl6-nixos-system-nixos-26.05.20260809.fcb8fcd/bin/switch-to-configuration switch' returned non-zero exit status 4.