Bump version to 0.5.0

Bump version to 0.4.7

Release 0.4.1: Pragmatic highlight system

Key improvements:
- Occurrence-based text search with whitespace normalization
- Server-side markdown injection for reliable rendering
- Aggressive stale detection with graceful failure
- Comprehensive documentation

This release implements a working highlight system that handles
common cases well and fails safely for edge cases.