chore: add 7-day cooldown to dependabot github-actions updates

[ted-palmer]

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Project	Deployment	Actions	Updated (UTC)
relay-sdk-demo	Ready	Preview, Comment	May 15, 2026 6:54pm

[github-actions]

Claude finished @ted-palmer's task in 22s —— View job

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Code Review — No issues found.

Reviewed 1 file, 2 lines changed. Checked for correctness, security, error handling, and repo guidelines compliance.

The cooldown.default-days: 7 setting is a valid Dependabot configuration option that delays new updates for 7 days after a release, giving the ecosystem time to surface regressions before bumping. Scoping it to the github-actions ecosystem only (and not the npm block, which already has open-pull-requests-limit: 0) is consistent with the existing config intent.
• Branch

[github-actions]

Claude finished @ted-palmer's task in 26s —— View job

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📝 Docs Drift Check — No docs impact

This PR does not touch surfaces that require a relayprotocol/relay-docs update.

• Branch: ted/dependabot-github-actions-cooldown