fix(dependabot): Remove empty ignore array causing validation error

[yunseo-kim]

Summary

Fixes Dependabot configuration validation error by removing the empty ignore array.

• What changed? Removed the ignore: [] property from the npm package ecosystem configuration in .github/dependabot.yml
• Why is this needed? The property '#/updates/0/ignore' did not contain a minimum number of items (1). When no packages need to be ignored, the property should be omitted entirely rather than provided as an empty array.

Related Issues

• N/A (validation error observed in repository settings)

Change Type

• Bug fix
• Feature
• Refactor
• Documentation
• Test/CI
• Breaking change
• Other:

Checklist

General

• PR title follows Conventional Commits format: type(scope): Summary
• This PR does not expose backend/internal implementation details in a public repo.
• No secrets, tokens, keys, or private endpoints are included.
• Changes stay within this repository's intended scope.

CI/Workflow Changes (if applicable)

• All uses: references are pinned to full 40-character commit SHAs (with # vX.Y.Z comment)
• step-security/harden-runner is included as the first step in every job
• Job-level permissions are used instead of top-level permissions

Protocol / Compatibility Impact

• No protocol/spec impact

Testing

• Unit tests added/updated
• Integration or conformance tests added/updated
• Tests pass
• Lint and format pass
• Type check passes
• Manual verification performed

Describe test evidence: The dependabot.yml file was validated and the error no longer appears. Pre-commit hooks passed successfully.

Documentation

• README updated
• Spec/docs updated
• Changelog/release notes updated (if needed)

Rollout / Risk

• Risk level: Low
• Rollback plan: Revert this single commit if needed