also document why transmission-gc talks to 128.0.0.1: the daemon runs in its
own netns (t1), the gc unit does not (t2), so localhost is not the daemon.

mpvpaper rendered a looping video on every output, which makes every frame
full-screen motion. On the sunshine-streamed tablet screen that meant a
constantly saturated encoder and an unusable stream (97% of frames dropped
at 5 Mbps), and on the real outputs it is pointless power draw.

noctalia owns the desktop background again (wallpaper.enabled = true); pick
the image in its wallpaper panel. ~/wallpaper is no longer seeded, but
lockscreen still uses whatever is in it.

Streams a sway headless output to Moonlight with Sunshine, so an Android
tablet works as a wireless second screen with its touchscreen acting as a
touchpad on the shared cursor.

The output is created once per session and stays disabled until a client
streams: sunshine's prep-cmd enables it at exactly the resolution and
refresh rate the client asks for, and disables it afterwards so sway moves
the workspace back to the real screens. wlroots never reuses a headless
output name, so the name is discovered at creation time, remembered in
$XDG_RUNTIME_DIR and handed to sunshine as an output_name command line
override instead of being hardcoded.

Replaces 2configs/sunshine.nix, which only shipped a manual launcher
script.

styx keeps hass/snapserver/mycelium as a plain LAN client on et0 with a
static lease (10.42.0.3) from acheron; 10.42.0.1 now means the router.
Repoint snapclient, mycelium peers, zigbee2mqtt broker, ignavia's tinc
Address and the gg23 extraHosts accordingly.

Intel N355 mini PC, 2x I226-V, UEFI/NVMe disko, systemd-boot. Only
2configs + retiolum + gg23 for now; NIC naming matches styx (et0 uplink,
int0 LAN). Retiolum card in retiolum/ (10.243.11.2), server tag.