feat(release): prepare v0.4.3 beta release

Prepare the v0.4.3 beta release with major feature additions and improvements:
- Add JsonXPathExtractionStrategy and LLMContentFilter to exports
- Update version to 0.4.3b1
- Improve documentation for dispatchers and markdown generation
- Update development status to Beta
- Reorganize changelog format

BREAKING CHANGE: Memory threshold in MemoryAdaptiveDispatcher increased to 90% and SemaphoreDispatcher parameter renamed to max_session_permit

docs/examples/dispatcher_example.py

@@ -12,6 +12,7 @@ from crawl4ai import (
     CrawlerMonitor,
     DisplayMode,
     CacheMode,
+    LXMLWebScrapingStrategy,
 )
 
 
@@ -113,7 +114,7 @@ def create_performance_table(results):
 async def main():
     urls = [f"https://example.com/page{i}" for i in range(1, 20)]
     browser_config = BrowserConfig(headless=True, verbose=False)
-    run_config = CrawlerRunConfig(cache_mode=CacheMode.BYPASS)
+    run_config = CrawlerRunConfig(cache_mode=CacheMode.BYPASS, scraping_strategy=LXMLWebScrapingStrategy())
 
     results = {
         "Memory Adaptive": await memory_adaptive(urls, browser_config, run_config),