Add goTool autotest with bench configs and UART scenarios.

JSON configs describe network and node MACs; scenarios run command
sequences with expect checks. Share UART client API across CLI and tests.

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

goTool/testdata/README.md

@@ -0,0 +1,47 @@
+# goTool autotest fixtures
+
+## Bench config (`configs/*.json`)
+
+Describes your hardware bench (for documentation and slave lookup in tests).
+
+| Field | Meaning |
+|-------|---------|
+| `id` | Config name; referenced by scenarios |
+| `network` | ESP-NOW network **1–8** (must match DIP/IO expander on all nodes) |
+| `master_mac` | Expected WiFi MAC of the master ESP (reference) |
+| `slaves[].id` | Short name used in scenario `input.slave` / `expect.slave` |
+| `slaves[].mac` | Full slave STA MAC (must match `gotool clients`) |
+| `slaves[].client_id` | Optional; default = last MAC byte |
+
+Copy `example-lab.json` to e.g. `my-lab.json` and set real MACs.
+
+## Scenario (`scenarios/*.json`)
+
+Ordered steps: UART commands with `input` and `expect`.
+
+| Step field | Meaning |
+|------------|---------|
+| `delay_ms` | Sleep only (no command) |
+| `command` | `version`, `clients`, `deadzone`, `unicast_test` |
+| `input` | Command arguments (see below) |
+| `expect` | Assertions on the response |
+
+### Commands
+
+**version** — `expect`: `version`, `version_min`, `git_hash`
+
+**clients** — `expect`: `min_clients`, `max_clients`, `client_count`, `slave` / `slaves`, `available`
+
+**deadzone** — `input`: `write`, `value`/`deadzone`, `slave` or `client`/`client_id`, `all_clients`  
+`expect`: `deadzone`, `success`, `slaves_updated`, `slaves_updated_min`
+
+**unicast_test** — `input`: `slave` or `client_id`, `seq`  
+`expect`: `success`, `seq`
+
+### Example
+
+```bash
+cd goTool
+go run . -port /dev/ttyUSB0 test -config my-lab -scenario smoke
+go run . -port /dev/ttyUSB0 test -list-configs
+```