feat(scraping): add LXML-based scraping mode for improved performance

Adds a new ScrapingMode enum to allow switching between BeautifulSoup and LXML parsing.
LXML mode offers 10-20x better performance for large HTML documents.

Key changes:
- Added ScrapingMode enum with BEAUTIFULSOUP and LXML options
- Implemented LXMLWebScrapingStrategy class
- Added LXML-based metadata extraction
- Updated documentation with scraping mode usage and performance considerations
- Added cssselect dependency

BREAKING CHANGE: None

pyproject.toml

@@ -35,6 +35,7 @@ dependencies = [
     "playwright",
     "aiofiles",
     "rich>=13.9.4",
+    "cssselect>=1.2.0",
 ]
 classifiers = [
     "Development Status :: 3 - Alpha",