fix(docker): pin playwright browser install to lockfile version

The chromium stage used npx playwright@1 (latest 1.x) to install
the browser, but the release stage installs playwright@1.59.1 from
the lockfile. When a newer playwright 1.x was released, the browser
revision installed in the chromium stage no longer matched what the
app expected, causing "Executable doesn't exist" on startup.

Pin to 1.59.1 to match pnpm-lock.yaml.

Author: edwardlonsdale

Dockerfile

@@ -9,7 +9,7 @@ RUN apt-get update && apt-get install -y \
   && rm -rf /var/lib/apt/lists/*
 
 ENV PLAYWRIGHT_BROWSERS_PATH=/pw-browsers
-RUN npx playwright@1 install chromium
+RUN npx playwright@1.59.1 install chromium
 
 FROM node:${NODE_IMAGE_TAG} AS build