Resilience : ecran pause, reconnexion WS auto, watchdog systemd, WiFi monitor

- WebSocket : reconnexion avec backoff exponentiel au lieu de reload page
- Ecran pause avec tasse de cafe quand le backend est injoignable
- Endpoint /api/health pour monitoring externe
- Watchdog systemd (sd_notify READY=1 + WATCHDOG=1 toutes les 10s)
- Service systemd durci (Type=notify, WatchdogSec=30, KillMode, limites)
- WiFi watchdog : script + timer systemd, verifie la gateway toutes les 60s
- Destinations : fallback url_tunnel (WireGuard) en priorite

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

scripts/photobooth.service

@@ -1,15 +1,25 @@
 [Unit]
-Description=Photobooth
+Description=Photobooth backend
 After=network.target graphical.target
+Wants=graphical.target
 
 [Service]
-Type=simple
+Type=notify
 User=jules
-WorkingDirectory=/home/jules/Documents/Projet/photobooth-app
-ExecStart=/home/jules/Documents/Projet/photobooth-app/scripts/start.sh
+WorkingDirectory=/home/jules/photobooth
+ExecStart=/home/jules/photobooth/scripts/start.sh
+ExecStopPost=/bin/bash -c 'pkill -9 -f "python.*backend.main" 2>/dev/null; sleep 1'
 Restart=always
-RestartSec=5
+RestartSec=3
+WatchdogSec=30
+KillMode=control-group
+KillSignal=SIGTERM
+TimeoutStopSec=10
+StartLimitIntervalSec=120
+StartLimitBurst=10
 Environment=DISPLAY=:0
+Environment=XAUTHORITY=/home/jules/.Xauthority
+AmbientCapabilities=CAP_NET_BIND_SERVICE
 
 [Install]
 WantedBy=graphical.target

scripts/wifi-watchdog.service

@@ -0,0 +1,6 @@
+[Unit]
+Description=WiFi watchdog check
+
+[Service]
+Type=oneshot
+ExecStart=/home/jules/photobooth/scripts/wifi-watchdog.sh

scripts/wifi-watchdog.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+# Surveille la connexion WiFi et la rétablit si elle tombe.
+# Conçu pour Surface Pro (wlan0) — lancé par cron ou systemd timer.
+
+IFACE="wlan0"
+GATEWAY=$(ip route show default dev "$IFACE" 2>/dev/null | awk '{print $3}' | head -1)
+LOG_TAG="wifi-watchdog"
+
+if [ -z "$GATEWAY" ]; then
+    logger -t "$LOG_TAG" "Pas de gateway sur $IFACE, tentative reconnexion..."
+    nmcli device connect "$IFACE" 2>&1 | logger -t "$LOG_TAG"
+    sleep 5
+    GATEWAY=$(ip route show default dev "$IFACE" 2>/dev/null | awk '{print $3}' | head -1)
+fi
+
+if [ -n "$GATEWAY" ]; then
+    if ! ping -c 2 -W 3 -I "$IFACE" "$GATEWAY" > /dev/null 2>&1; then
+        logger -t "$LOG_TAG" "Ping gateway $GATEWAY echoue, reconnexion WiFi..."
+        nmcli device disconnect "$IFACE" 2>&1 | logger -t "$LOG_TAG"
+        sleep 2
+        nmcli device connect "$IFACE" 2>&1 | logger -t "$LOG_TAG"
+        sleep 5
+        if ! ping -c 2 -W 3 -I "$IFACE" "$GATEWAY" > /dev/null 2>&1; then
+            logger -t "$LOG_TAG" "Toujours pas de connexion, restart NetworkManager..."
+            systemctl restart NetworkManager
+        fi
+    fi
+fi

scripts/wifi-watchdog.timer

@@ -0,0 +1,9 @@
+[Unit]
+Description=WiFi watchdog - check every minute
+
+[Timer]
+OnBootSec=30
+OnUnitActiveSec=60
+
+[Install]
+WantedBy=timers.target