feat: monitoring exporters, alerting, rate limiting, backups, incident runbook

- Add 4 Prometheus exporters: nginx (9113), redis (9121), postgres (9187), node (9100)
- Create 8 alerting rules in monitoring/prometheus/alerts.yml
- Update prometheus.yml with all scrape targets + rule_files
- WS connection rate limiting: max 5/IP/60s (Redis INCR)
- Admin login rate limiting: max 5/IP/5min (Redis INCR)
- 3 backup scripts: daily to R2 (14d), weekly full (8w), verify with restore test
- docs/incident-runbook.md with 5-tier triage + escalation
- Update CD workflow: full prometheus config + alerts seeding

scripts/backup-weekly.sh

@@ -0,0 +1,48 @@
+#!/bin/bash
+# Weekly full PostgreSQL backup to R2 (8-week retention)
+# Schedule: cron weekly (runs backup-db.sh with weekly prefix)
+set -e
+
+BACKUP_DIR="${BACKUP_DIR:-/tmp/linearvoid-backups}"
+RETENTION_WEEKS="${RETENTION_WEEKS:-8}"
+R2_BUCKET="${R2_BUCKET:-linearvoid-backups}"
+DB_URL="${DATABASE_URL:-postgres://linearvoid:linearvoid@db:5432/linearvoid?sslmode=disable}"
+
+TIMESTAMP=$(date +%Y%m%d)
+BACKUP_FILE="$BACKUP_DIR/weekly/db_${TIMESTAMP}.dump"
+
+mkdir -p "$(dirname "$BACKUP_FILE")"
+
+echo "[$(date -Iseconds)] Starting weekly full backup..."
+
+DB_HOST=$(echo "$DB_URL" | sed -n 's/.*@\([^:]*\).*/\1/p')
+DB_PORT=$(echo "$DB_URL" | sed -n 's/.*:\([0-9]*\)\/.*/\1/p')
+DB_USER=$(echo "$DB_URL" | sed -n 's/.*:\/\/\([^:]*\).*/\1/p')
+DB_NAME=$(echo "$DB_URL" | sed -n 's/.*\/\([^?]*\).*/\1/p')
+DB_PASS=$(echo "$DB_URL" | sed -n 's/.*:\/\/[^:]*:\([^@]*\).*/\1/p')
+
+export PGPASSWORD="${DB_PASS}"
+
+pg_dump -h "${DB_HOST:-db}" -p "${DB_PORT:-5432}" -U "${DB_USER:-linearvoid}" \
+        -Fc -f "$BACKUP_FILE" "${DB_NAME:-linearvoid}"
+
+echo "  Backup: $BACKUP_FILE ($(du -h "$BACKUP_FILE" | cut -f1))"
+
+# Verify integrity
+pg_restore --list "$BACKUP_FILE" > /dev/null 2>&1 && \
+    echo "  Integrity check: PASSED" || \
+    echo "  WARNING: Integrity check FAILED"
+
+# Upload
+if [ -n "$R2_ENDPOINT" ] && [ -n "$R2_ACCESS_KEY_ID" ]; then
+    aws s3 cp "$BACKUP_FILE" "s3://${R2_BUCKET}/weekly/db_${TIMESTAMP}.dump" \
+        --endpoint-url "$R2_ENDPOINT" --no-verify-ssl 2>/dev/null && \
+        echo "  Uploaded to R2: weekly/db_${TIMESTAMP}.dump" || \
+        echo "  WARNING: R2 upload failed"
+fi
+
+# Cleanup
+find "$BACKUP_DIR/weekly" -name "db_*.dump" -mtime "+$((RETENTION_WEEKS * 7))" -delete 2>/dev/null || true
+echo "  Cleaned up backups older than ${RETENTION_WEEKS} weeks"
+
+echo "[$(date -Iseconds)] Weekly backup complete."