feat(reliability): risky-op preflight snapshots + detached rollback watchdog

payload/user/remote_access/pager-webui/mk8-watchdog.sh

@@ -0,0 +1,30 @@
+#!/bin/sh
+# Usage: mk8-watchdog.sh <profile> <interval> <fail_after> <healthy_after>
+PROFILE="$1"; IV="${2:-5}"; FA="${3:-6}"; HA="${4:-6}"
+DIR="/root/payloads/user/remote_access/pager-webui"
+[ -f "$DIR/server.py" ] || DIR="/mmc/mk8/releases/current"
+fails=0; oks=0; tripped=0
+probe() {
+    curl -fsS -m 3 http://127.0.0.1:8080/ >/dev/null 2>&1 &&
+    { ip link show wlan0mon >/dev/null 2>&1 ||
+      ip link show wlan1mon >/dev/null 2>&1; }
+}
+while true; do
+    if probe; then
+        fails=0
+        if [ "$tripped" = "1" ]; then
+            oks=$((oks + 1))
+            if [ "$oks" -ge "$HA" ]; then
+                /usr/bin/python3 "$DIR/server.py" --promote-snapshot "$PROFILE" >/dev/null 2>&1
+                exit 0
+            fi
+        fi
+    else
+        fails=$((fails + 1)); oks=0
+        if [ "$tripped" = "0" ] && [ "$fails" -ge "$FA" ]; then
+            tripped=1
+            /usr/bin/python3 "$DIR/server.py" --rollback-snapshot "$PROFILE" >/dev/null 2>&1
+        fi
+    fi
+    sleep "$IV"
+done