Add bench UART ports and cold-start reset to goTool autotest.

Bench configs define command and console serial paths; scenarios can
reset nodes via esptool before tests. Smoke resets all nodes then waits
for ESP-NOW join.

Co-authored-by: Cursor <cursoragent@cursor.com>

goTool/testdata/scenarios/smoke.json

@@ -1,21 +1,29 @@
 {
   "id": "smoke",
-  "description": "Basic master UART checks (no slaves required for version)",
+  "description": "Cold-start smoke: reset all nodes, wait for join, then UART checks",
   "config": "example-lab",
   "steps": [
     {
-      "name": "firmware version",
+      "name": "reset all nodes",
+      "command": "reset",
+      "input": {
+        "all": true,
+        "wait_ms": 2500
+      }
+    },
+    {
+      "name": "boot and ESP-NOW join",
+      "delay_ms": 10000
+    },
+    {
+      "name": "master UART up",
       "command": "version",
       "expect": {
         "version_min": 1
       }
     },
     {
-      "name": "wait for ESP-NOW join",
-      "delay_ms": 5000
-    },
-    {
-      "name": "slave visible",
+      "name": "slave registered",
       "command": "clients",
       "expect": {
         "min_clients": 1,