Stop an unused apt source being able to fail CI

[bazauto]

CI has been failing on every branch since around 17:30 on 2026-09-09, at the
Install Playwright browser step, with Hash Sum mismatch and exit 100. It is not the
diff on any of those branches, and it is not a flake — two reruns twelve minutes apart
failed identically.

npx playwright install --with-deps chromium runs apt-get update before installing the
system libraries Chromium links against. apt-get update fails as a whole if any
configured source is broken, including one nothing here uses — and the GitHub runner image
ships Google's Chrome apt repo preconfigured.

That repo is currently serving an internally inconsistent index. Fetched directly, outside
GitHub, to rule out the runner and its mirror:

Release claims  SHA256 233e56de019b57db89238fa7bcc3647718dbbea3a40c2dc1c633a8c8952aa9e9
Actually served SHA256 bc1428ab27c6d76ee9bb76de07f1ded0ddb4aaabd958fc72855634ef5894a4b3
                       (main/binary-amd64/Packages.gz, both 1405 bytes)

So apt is right to refuse it, and the job dies before a single e2e test runs.

The fix, and why removal rather than a retry

Nothing in this repo installs Google Chrome. Playwright downloads its own Chromium build;
--with-deps only pulls distro packages, all from Ubuntu's own archives. The Google source
contributes nothing to this job and can only ever subtract from it.

Removing it is therefore the fix rather than wrapping the step in a retry:

• a retry would not have helped — the index stayed inconsistent across both reruns
• a third party the build does not depend on should not be able to fail the build
• it is one line, and it removes the dependency permanently rather than papering over an
  outage that will recur

sudo rm -f so the step is a no-op if a future runner image stops shipping that source.

Deliberately not done here: dropping --with-deps altogether and relying on the runner
image's preinstalled browser libraries. That would also dodge apt, but it trades a stated
dependency for an assumption about the image, and the next image change breaks e2e with a
missing-shared-library error rather than a clear one.

Verification

The honest check on this one is CI itself — this changes only the workflow, and the step it
fixes is the step that was failing, so a green run on this PR is the test. Locally the
workflow still parses and the job's steps are unchanged in name and order:

Use Node.js / Install dependencies / Lint / Run tests / Build backend /
Build frontend / Install Playwright browser / Run e2e tests / Upload Playwright evidence

Nothing outside .github/workflows/ci.yml is touched, so no repo docs are falsified.

Unblocks #186.

🤖 Generated with Claude Code

https://claude.ai/code/session_01SQMPj8UFbx1AwH3QgttGRV