chore: use shared Renovate preset

[haasonsaas]

Summary

• add or normalize renovate.json to extend the shared evalops/.github Renovate preset
• remove Dependabot config where this repo is migrated to Renovate

Refs evalops/deploy#53.

Validation

• configuration matches the deploy repo Renovate onboarding pattern and shared org preset

[cursor]

PR Summary

Low Risk
Config-only change affecting automated dependency update tooling; no runtime code paths are modified.

Overview
Switches Renovate configuration to a minimal renovate.json that extends the shared local>evalops/.github:renovate-config preset, removing repo-specific rules/labels.

Removes .github/dependabot.yml, completing the migration from Dependabot-managed updates to Renovate-managed updates.

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