chore: inherit automerge from the shared Renovate preset

[mikaello]

Changes

• Remove the local automerge rule and inherit minor, patch, pin and digest automerge from github>mikaello/renovate-presets.
• Use the shared Sunday 22:00–Monday 08:00 Europe/Oslo window leading into odd ISO weeks.
• Keep the shared GitHub Actions major-update exceptions.

The shared change is merged in mikaello/renovate-presets#3.

Verification

• Strict Renovate repository config validation passed.
• Config formatting and git diff --check passed.
• Checked effective automerge and TypeScript rules against the updated shared preset across all 43 active projects.