Enable ANN205: Detect missing return type on static methods

## Rule

**ANN205**: `missing-return-type-static-method`

## Purpose

Ensure all static methods have explicit return type annotations for better type safety and documentation.

## Auto-fix

❌ Not available - requires manual annotation

## Notes

- Part of comprehensive type annotation enforcement
- Helps catch potential type mismatches at static analysis time

JIRA Issue: BA-4019