v4: the devcontainer has Playwright's browsers — they were installed by hand in the home directory, which the rebuild onto Node 26 left without them, and the screenshots of the dev instances stopped working. The Dockerfile installs Firefox and the Chromium headless shell of npm:playwright@1.63.0, with the system libraries they need, in /opt/ms-playwright (PLAYWRIGHT_BROWSERS_PATH), which the workspace and the instances' services share as part of the image.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.devcontainer/Dockerfile

@@ -6,6 +6,15 @@ COPY --from=deno /deno /usr/local/bin/deno
 RUN apt-get update \
   && apt-get install -y --no-install-recommends ffmpeg \
   && rm -rf /var/lib/apt/lists/*
+# Playwright's Firefox and Chromium headless shell, with the system libraries
+# they need, for screenshots of the dev instances (`npm:playwright@1.63.0`): a
+# script importing another version looks for other builds. They live outside
+# the home directory, which a rebuild would otherwise leave without them.
+ENV PLAYWRIGHT_BROWSERS_PATH=/opt/ms-playwright
+RUN DENO_DIR=/tmp/deno deno run --no-lock -A npm:playwright@1.63.0 install \
+    --with-deps firefox chromium-headless-shell \
+  && chmod -R a+rX /opt/ms-playwright \
+  && rm -rf /tmp/deno /var/lib/apt/lists/*
 # The services share Deno's cache through a volume (compose.yaml), which Docker
 # creates owned as this directory is, so it must exist and be node's.
 RUN mkdir -p /home/node/.cache/deno && chown -R node:node /home/node/.cache