The search functionality was silently dropping CJK characters because:
1. Query sanitization used `\w` which only matches ASCII word characters
2. Stemmer split by whitespace, which doesn't work for CJK languages
3. Highlighter used `\b` word boundaries that don't apply to CJK
This commit fixes all three issues:
- Query: Use `\p{L}\p{N}` (Unicode letters/numbers) instead of `\w`
- Stemmer: Preserve CJK characters as-is without stemming, since CJK
languages don't have stemming rules like English
- Highlighter: Skip word boundary matching for CJK terms
Also extracts `CJK_PATTERN` to `Search` module to avoid duplication.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
LU
2a4fbecbda