Add serial dev commands and a serial log helper

The firmware accepts burst, key <name>, sound on|off and short|normal
over serial, so UI behaviour can be reproduced on the device without
the keyboard. scripts/serial_log.sh records (and drives) it in a named
container that flash.sh removes before uploading.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

scripts/flash.sh

@@ -5,6 +5,7 @@ set -euo pipefail
 PORT="${1:-$(readlink -f /dev/serial/by-id/*Espressif* 2>/dev/null | head -1)}"
 [ -n "$PORT" ] || { echo "No Cardputer found on USB (is it plugged in / attached to the VM?)" >&2; exit 1; }
 source "$(dirname "$0")/_docker.sh"
+docker rm -f roro9stack-serial >/dev/null 2>&1 || true  # a serial log would hold the port
 DOCKER_EXTRA=(--device "$PORT" --group-add "$(stat -c %g "$PORT")" -it)
 
 run_in_container bash -c "git config --global --add safe.directory /work && pio run -e cardputer-adv -t upload --upload-port $PORT && pio device monitor -p $PORT -b 115200"

scripts/serial_log.py

@@ -0,0 +1,30 @@
+# Reads the Cardputer's serial port, reconnecting when it re-enumerates. Run via serial_log.sh.
+import glob, os, sys, time
+import serial
+
+end = time.time() + float(sys.argv[1])
+commands = sys.argv[2:]  # sent once after connecting, e.g. "burst"
+while time.time() < end:
+    ports = glob.glob('/dev/serial/by-id/*Espressif*')
+    if not ports:
+        time.sleep(1)
+        continue
+    try:
+        s = serial.Serial(os.path.realpath(ports[0]), 115200, timeout=0.2)
+        print('[connected]', flush=True)
+        for c in commands:  # "sleep:N" waits N seconds between commands
+            if c.startswith('sleep:'):
+                time.sleep(float(c[6:]))
+                continue
+            time.sleep(1)
+            s.write((c + '\n').encode())
+        commands = []
+        buf = b''
+        while time.time() < end:
+            buf += s.read(512)
+            while b'\n' in buf:
+                line, buf = buf.split(b'\n', 1)
+                print(line.decode(errors='replace').rstrip(), flush=True)
+    except Exception as e:
+        print('[disconnected]', e, flush=True)
+        time.sleep(1)

scripts/serial_log.sh

@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+# Dev helper: record the Cardputer's serial output for N seconds (follows port changes).
+# Usage: scripts/serial_log.sh [seconds] [command...]   — stop early with: docker rm -f roro9stack-serial
+set -euo pipefail
+source "$(dirname "$0")/_docker.sh"
+docker rm -f roro9stack-serial >/dev/null 2>&1 || true
+DOCKER_EXTRA=(--name roro9stack-serial --group-add "$(getent group dialout | cut -d: -f3)" --privileged -v /dev:/dev)
+run_in_container /pio/penv/bin/python scripts/serial_log.py "${1:-60}" "${@:2}"