Add no-cache response header to dashboard for immediate visibility after deploys; enhance Proxmox monitoring documentation and update flash script to allow Backup without a golden image.

chromium-setup/emmc-provisioning/scripts/monitor-from-host.sh

@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+# Run on the Proxmox HOST to see provisioning status, USB, flash job, and logs.
+# Usage: ./monitor-from-host.sh   or: ssh root@10.130.60.224 'bash -s' < scripts/monitor-from-host.sh
+
+PROV=/var/lib/cm4-provisioning
+
+echo "═══════════════════════════════════════════════════════════════"
+echo "  CM4 provisioning – host monitor"
+echo "═══════════════════════════════════════════════════════════════"
+echo ""
+
+echo "--- USB (CM4 boot mode: 2b8e or 0a5c:2711) ---"
+lsusb | grep -E "2b8e|0a5c" || echo "  No CM4 boot device seen."
+echo ""
+
+echo "--- Current status (dashboard reads this) ---"
+if [[ -f "$PROV/status.json" ]]; then
+  cat "$PROV/status.json" | python3 -m json.tool 2>/dev/null || cat "$PROV/status.json"
+else
+  echo "  No status.json (no run yet)."
+fi
+echo ""
+
+echo "--- Flash job (systemd unit) ---"
+systemctl show cm4-flash-once --property=ActiveState,SubState,ExecMainPID 2>/dev/null || echo "  Unit not run yet."
+echo ""
+
+echo "--- Last 20 lines of flash.log ---"
+tail -20 "$PROV/flash.log" 2>/dev/null || echo "  No flash.log"
+echo ""
+
+echo "--- Provisioning dir ---"
+ls -la "$PROV/" 2>/dev/null || echo "  Dir missing."
+echo ""
+
+echo "--- Block devices (eMMC appears here after rpiboot) ---"
+lsblk -d -o NAME,SIZE,MODEL,TRAN 2>/dev/null | head -15
+echo ""
+
+echo "--- Config ---"
+echo "  enabled:  $([ -f /etc/cm4-provisioning/enabled ] && echo yes || echo no)"
+echo "  rpiboot:  $([ -x /opt/usbboot/rpiboot ] && echo /opt/usbboot/rpiboot || echo MISSING)"
+echo "  golden:   $([ -f $PROV/golden.img ] && echo present || echo not set)"
+echo "  backups:  $(ls "$PROV/backups" 2>/dev/null | wc -l) file(s)"