Add start.sh with startup logging

start.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+set -e
+
+echo "=== SentinelScan Startup ==="
+echo "[startup] Checking Python..."
+python --version
+
+echo "[startup] Testing app import..."
+python -c "
+import sys, os
+sys.path.insert(0, os.path.abspath('backend_structured'))
+from backend_structured import create_app
+app = create_app()
+print('[startup] App imported OK, routes:', len(list(app.url_map.iter_rules())))
+" 2>&1
+
+echo "[startup] Starting gunicorn..."
+exec gunicorn --bind 0.0.0.0:7860 --workers 1 --timeout 300 \
+  --access-logfile - --error-logfile - \
+  app:app