Remove redundant default Renovate settings

[ctreffs]

Context & Summary

What

• Removed redundant properties from .github/renovate.json that match Renovate's built-in default behavior:
  • "assignees": [] (docs)
  • "automergeType": "pr" (docs)
  • "prCreation": "not-pending" (docs)
  • "recreateWhen": "auto" (docs)
  • "reviewers": [] (docs)
  • "reviewersFromCodeOwners": false (docs)

Why

• Simplifies .github/renovate.json by retaining only necessary overrides and custom rules.
• Restores Renovate's default immediate PR creation behavior.

Where

• .github/renovate.json

---

Reviewer Guidance

How to Test / Verify

1. Run local validation:

   npx --yes --package renovate -- renovate-config-validator .github/renovate.json

2. Confirm the validator passes with zero warnings or errors.

Risk of Regression

• Low: Removes only default settings without changing expected Renovate behavior.

Focus Areas

• .github/renovate.json: Verify remaining settings retain custom package rules, labels, and notification suppressions.