tools: add screenshot.sh screen-grabber wrapper

One-command screenshot helper around gd-77_screen_grabber.py: auto-detects the
radio's serial port (cu.usbmodem* on macOS, ttyACM* on Linux) and creates a
self-contained Python venv with pyserial + pillow on first run. Saves to
screenshots/ (gitignored, along with the venv). Documented in TOOLS.md.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitignore

@@ -8,3 +8,7 @@ languages_builder
 
 # Generated docs site
 website/_build/
+
+# Screenshot tool venv + scratch output
+MDUV380_firmware/tools/.venv/
+screenshots/

CHANGELOG.md

@@ -7,7 +7,9 @@ single running list until the first versioned release.
 
 ## Unreleased
 
-_Nothing yet._
+- **`screenshot.sh`** — a one-command wrapper around the OpenGD77 screen grabber
+  that auto-detects the serial port and sets up a self-contained Python venv
+  (pyserial + pillow) on first run. Saves to `screenshots/`.
 
 ## 0.5.0
 

TOOLS.md

@@ -87,9 +87,19 @@ Models: `MD-UV380`, `DM-1701`, `MD-9600`, `MD-2017`, `MD-380`.
 grabber (the "gd-77" name is historical). It talks over the USB **CDC serial port**,
 auto-detects the radio model and reads the MD-UV380's 160×128 RGB565 framebuffer into a PNG.
 
-1. Power the radio on **normally** (not DFU mode) and navigate to the screen you want.
-   Connect USB.
-2. Run it (`-o` takes the filename **without** `.png`):
+Power the radio on **normally** (not DFU mode), navigate to the screen you want, and
+connect USB.
+
+**Easiest — the `./screenshot.sh` helper** (auto-detects the serial port and sets up a
+self-contained Python venv with `pyserial` + `pillow` on first run):
+
+```bash
+./screenshot.sh                 # -> screenshots/screenshot-<timestamp>.png
+./screenshot.sh vfo-7seg        # -> screenshots/vfo-7seg.png
+./screenshot.sh -d /dev/cu.usbmodemXXXX [name]   # explicit port
+```
+
+**Or call the grabber directly** (`-o` takes the filename **without** `.png`):
 
 ```bash
 python3 MDUV380_firmware/tools/gd-77_screen_grabber.py \

screenshot.sh

@@ -0,0 +1,55 @@
+#!/usr/bin/env bash
+#
+# Grab a screenshot from the radio over USB (CDC serial), using the OpenGD77
+# screen grabber. Runs natively (USB serial is not available inside Docker) and
+# sets up a self-contained Python venv (pyserial + pillow) on first use.
+#
+# The radio must be powered on, running the firmware, and connected via USB.
+#
+# Usage:
+#   ./screenshot.sh                       # auto-detect port -> screenshots/screenshot-<timestamp>.png
+#   ./screenshot.sh vfo-7seg              # -> screenshots/vfo-7seg.png
+#   ./screenshot.sh -d /dev/cu.usbmodem1234 [name]   # explicit serial port
+set -euo pipefail
+
+REPO_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+GRABBER="$REPO_DIR/MDUV380_firmware/tools/gd-77_screen_grabber.py"
+VENV="$REPO_DIR/MDUV380_firmware/tools/.venv"
+OUT_DIR="$REPO_DIR/screenshots"
+
+# ---- optional explicit device (-d /dev/...) -------------------------------
+DEVICE=""
+if [[ "${1:-}" == "-d" ]]; then
+	DEVICE="${2:-}"; shift 2 || true
+fi
+
+# ---- auto-detect the radio's serial port ----------------------------------
+if [[ -z "$DEVICE" ]]; then
+	case "$(uname -s)" in
+		Darwin) DEVICE="$(ls /dev/cu.usbmodem* 2>/dev/null | head -1 || true)" ;;
+		*)      DEVICE="$(ls /dev/ttyACM* 2>/dev/null | head -1 || true)" ;;
+	esac
+fi
+if [[ -z "$DEVICE" ]]; then
+	echo "!! No radio serial port found." >&2
+	echo "   Connect the radio via USB (powered on, running firmware) and retry, or pass one:" >&2
+	echo "     ./screenshot.sh -d /dev/cu.usbmodemXXXX" >&2
+	exit 1
+fi
+
+# ---- one-time Python venv with the grabber's dependencies ------------------
+if [[ ! -x "$VENV/bin/python" ]]; then
+	echo "==> First run: creating Python venv with pyserial + pillow..."
+	python3 -m venv "$VENV"
+	"$VENV/bin/pip" install --quiet --upgrade pip
+	"$VENV/bin/pip" install --quiet pyserial pillow
+fi
+
+# ---- output name -----------------------------------------------------------
+mkdir -p "$OUT_DIR"
+NAME="${1:-screenshot-$(date +%Y%m%d-%H%M%S)}"
+OUT="$OUT_DIR/$NAME"
+
+echo "==> Grabbing from $DEVICE"
+"$VENV/bin/python" "$GRABBER" -d "$DEVICE" -o "$OUT"
+echo "==> Saved: $OUT.png"