feat(geoportal): N8N webhook on sync completion + tile cache monitoring

- weekend-deep-sync.ts: fire webhook to N8N_WEBHOOK_URL after each sync cycle
  (N8N triggers tippecanoe PMTiles rebuild via SSH on host)
- nginx tile-cache: add stub_status at /status, custom log format with cache status
- Add tile-cache-stats.sh: shows HIT/MISS ratio, cache size, slow tiles
- docker-compose: add N8N_WEBHOOK_URL env var

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/tile-cache-stats.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+# tile-cache-stats.sh — Show tile cache hit/miss statistics
+# Usage: ./scripts/tile-cache-stats.sh [MINUTES]
+# Reads recent nginx logs from tile-cache container.
+
+set -euo pipefail
+
+MINUTES="${1:-60}"
+
+echo "=== Tile Cache Stats (last ${MINUTES}min) ==="
+echo ""
+
+# Get nginx status (active connections)
+echo "--- Connections ---"
+curl -s "http://10.10.10.166:3010/status" 2>/dev/null || echo "(status endpoint unavailable)"
+echo ""
+
+# Parse recent logs for cache hit/miss ratio
+echo "--- Cache Performance ---"
+docker logs tile-cache --since "${MINUTES}m" 2>/dev/null | \
+  grep -oP 'cache=\K\w+' | sort | uniq -c | sort -rn || echo "(no logs in timeframe)"
+
+echo ""
+echo "--- Cache Size ---"
+docker exec tile-cache du -sh /var/cache/nginx/tiles/ 2>/dev/null || echo "(cannot read cache dir)"
+
+echo ""
+echo "--- Slowest Tiles (>1s) ---"
+docker logs tile-cache --since "${MINUTES}m" 2>/dev/null | \
+  grep -oP 'time=\K[0-9.]+' | awk '$1 > 1.0 {print $1"s"}' | sort -rn | head -5 || echo "(none)"