[ops] Fetch CBP wait times failing on main

[github-actions]

Workflow: Fetch CBP wait times
Commit: 7da461b
First failure: 2026-07-02T23:13:51.284Z

Subsequent failures are suppressed until this issue is closed.

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[sbc1-code]

Root cause: concurrent Pages deployments from deploy.yml and fetch-cbp.yml kill each other (both dispatched simultaneously during verification). Fixed in 9d55e3e: both workflows now share concurrency group pages with cancel-in-progress false, so deploys queue instead of racing. Verified by deliberately re-creating the collision: fetch-cbp queued behind the running deploy, then both went green with no annotations.