Add Go UART tool to query firmware VERSION over serial.

Framed protobuf client for /dev/ttyUSB0 at 921600 baud with generated
uart_messages types matching the device protocol.

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

goTool/README.md

@@ -0,0 +1,26 @@
+# goTool
+
+Host-side UART utilities for Powerpod.
+
+## version command
+
+Sends `MessageType.VERSION` (0x03) in a framed UART packet and prints the protobuf response.
+
+```bash
+cd goTool
+go mod tidy
+go run . -port /dev/ttyUSB0
+```
+
+Options:
+
+- `-port` — serial device (required)
+- `-baud` — default `921600` (must match firmware)
+
+## Regenerate protobuf
+
+```bash
+protoc --go_out=./pb --go_opt=paths=source_relative \
+  --go_opt=Muart_messages.proto=powerpod/gotool/pb \
+  -I ../main/proto ../main/proto/uart_messages.proto
+```