Sentry plumbing, inert until a DSN exists

Server: errors-only @sentry/node behind SENTRY_DSN, capturing the
unhandled-protocol catch with its message type and room. Client:
errors-only @sentry/browser behind VITE_SENTRY_DSN baked at build.
Backup: Sentry Crons check-ins (in_progress/ok/error) when
/root/.wizwar-sentry-cron holds the check-in URL. No DSN, no behavior.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015RCWSTnb1KYTPyL4GmhGnF

deploy/wizwar-backup.sh

@@ -8,6 +8,10 @@ BUCKET="kestrel-wizwar-backups"
 SRC="/var/lib/wizwar"
 LOG="/var/log/wizwar/backup.log"
 STAMP=$(date +%Y-%m-%d)
+# Sentry Crons check-in: /root/.wizwar-sentry-cron holds the check-in URL
+# (auto-creates the monitor on first ping). Absent file = no check-ins.
+CRON_URL=$(cat /root/.wizwar-sentry-cron 2>/dev/null || true)
+checkin() { [ -n "$CRON_URL" ] && curl -sf -o /dev/null "$CRON_URL?status=$1" || true; }
 
 if grep -q CHANGE_ME /root/.config/rclone/rclone.conf; then
   echo "$(date -Is) skipped: Spaces credentials not configured yet" >> "$LOG"
@@ -16,8 +20,13 @@ fi
 
 {
   echo "=== $(date -Is) backup start"
-  rclone sync "$SRC" "spaces:$BUCKET/wizwar/current" 2>&1
-  rclone copy "$SRC" "spaces:$BUCKET/wizwar/snapshots/$STAMP" 2>&1
+  checkin in_progress
+  if rclone sync "$SRC" "spaces:$BUCKET/wizwar/current" 2>&1 &&
+     rclone copy "$SRC" "spaces:$BUCKET/wizwar/snapshots/$STAMP" 2>&1; then
+    checkin ok
+  else
+    checkin error
+  fi
   # Prune dated snapshots older than 90 days (by directory name).
   CUTOFF=$(date -d "90 days ago" +%Y-%m-%d)
   rclone lsf "spaces:$BUCKET/wizwar/snapshots/" --dirs-only 2>/dev/null | \