Revert bun-canary CI quarantine after upstream restores linux glibc builds #2417

Context

Upstream oven-sh/bun canary rolling release stopped publishing the standard glibc Linux builds (bun-linux-x64.zip, bun-linux-aarch64.zip) on 2026-09-17 — every other variant (musl, baseline, darwin, windows, android, freebsd) present. oven-sh/setup-bun@v2 with bun-version: canary 404s, failing the bun canary matrix leg in .github/workflows/js.yml.

To unblock release v0.18.1 (PR #2415), the bun canary leg is quarantined with scoped continue-on-error + TODO.

Revert when

• https://github.com/oven-sh/bun/releases/download/canary/bun-linux-x64.zip returns 200 again, and
• a green bun canary run is observed after removing the quarantine.

Revert steps

1. Remove continue-on-error + TODO in .github/workflows/js.yml (build-and-test job).
2. Remove the maintenance checklist entry if it was only for this quarantine.
3. Close this issue.