fix: address verify findings - add visualize subcommand, curl healthcheck, IoU in JSON, 50KB threshold

scripts/run_e2e.sh

@@ -13,7 +13,7 @@ docker compose up -d
 
 echo "[2/5] Waiting for TDengine to be healthy..."
 for i in $(seq 1 60); do
-  if docker compose exec -T tdengine taos -s "SELECT SERVER_VERSION()" > /dev/null 2>&1; then
+  if curl -sf http://localhost:6041/rest/sql -d 'select server_version()' > /dev/null 2>&1; then
     echo "TDengine ready (attempt $i)"
     break
   fi
@@ -30,8 +30,8 @@ for png in render/*.png; do
   if [ -f "$png" ]; then
     sz=$(stat -c%s "$png" 2>/dev/null || stat -f%z "$png" 2>/dev/null || echo 0)
     echo "  $png: ${sz} bytes"
-    if [ "$sz" -lt 10240 ]; then
-      echo "  WARNING: PNG too small (< 10KB)"
+    if [ "$sz" -lt 51200 ]; then
+      echo "  WARNING: PNG too small (< 50KB)"
     fi
   fi
 done