Raspberry Pi Zero 2 W image builder; Power off/Restart buttons

pi/build-image.sh makes a ready-to-flash card: Raspberry Pi OS Lite 2026-10-06
+ the Gyre software as a service on http://gyre.local (port 80), first-boot
setup through cloud-init (user, SSH key, Wi-Fi, packages from the card), USB
host mode on the Zero 2's data port. No root: mtools for the boot partition,
debugfs for the root filesystem. Wi-Fi and credentials stay in the work dir.

Web page: Power off / Restart links when GYRE_POWER_BUTTONS=1 (set by the Pi
service); thumbnails keyed by file contents so pre-made ones ship on the card;
stale thumbnails pruned.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pi/overlay/etc/systemd/system/gyre.service

@@ -0,0 +1,17 @@
+[Unit]
+Description=Gyre sand art table: web page and pattern player
+Wants=network-online.target
+After=network-online.target
+
+[Service]
+User=gyre
+WorkingDirectory=/opt/gyre/software
+Environment=PYTHONUNBUFFERED=1 GYRE_POWER_BUTTONS=1
+ExecStart=/usr/bin/python3 -m sandtable web --host 0.0.0.0 --http-port 80 --no-browser
+# lets it use port 80 (so the address is just http://gyre.local) without running as root
+AmbientCapabilities=CAP_NET_BIND_SERVICE
+Restart=always
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target