Add end-to-end playwright test

e2e/run-e2e-local.sh

@@ -0,0 +1,38 @@
+#!/bin/bash
+set -euo pipefail
+
+# Run the E2E integration test with a visible browser window.
+# Usage: ./run-e2e-local.sh
+
+cd "$(dirname "$0")"
+
+FIRMWARE_VERSION="4.45.23646"
+FIRMWARE_URL="https://ereaderfiles.kobo.com/firmwares/kobo13/Mar2026/kobo-update-${FIRMWARE_VERSION}.zip"
+FIRMWARE_DIR="../kobopatch-wasm/testdata"
+FIRMWARE_FILE="${FIRMWARE_DIR}/kobo-update-${FIRMWARE_VERSION}.zip"
+
+if [ ! -f "../src/public/kobopatch.wasm" ]; then
+    echo "ERROR: kobopatch.wasm not found. Run kobopatch-wasm/build.sh first."
+    exit 1
+fi
+
+if [ ! -f "$FIRMWARE_FILE" ]; then
+    echo "Downloading firmware ${FIRMWARE_VERSION} (~150MB)..."
+    mkdir -p "$FIRMWARE_DIR"
+    curl -fL --progress-bar -o "$FIRMWARE_FILE.tmp" "$FIRMWARE_URL"
+    if ! file "$FIRMWARE_FILE.tmp" | grep -q "Zip archive"; then
+        echo "ERROR: downloaded file is not a valid zip"
+        rm -f "$FIRMWARE_FILE.tmp"
+        exit 1
+    fi
+    mv "$FIRMWARE_FILE.tmp" "$FIRMWARE_FILE"
+else
+    echo "Using cached firmware: $FIRMWARE_FILE"
+fi
+
+npm install --silent 2>/dev/null
+npx playwright install chromium 2>/dev/null
+
+echo "Running E2E integration test (headed)..."
+FIRMWARE_ZIP="$(cd .. && pwd)/kobopatch-wasm/testdata/kobo-update-${FIRMWARE_VERSION}.zip" \
+    npx playwright test --reporter=list --headed