feat(extraction): add RegexExtractionStrategy for pattern-based extraction

Add new RegexExtractionStrategy for fast, zero-LLM extraction of common data types:
- Built-in patterns for emails, URLs, phones, dates, and more
- Support for custom regex patterns
- LLM-assisted pattern generation utility
- Optimized HTML preprocessing with fit_html field
- Enhanced network response body capture

Breaking changes: None

crawl4ai/async_webcrawler.py

@@ -503,6 +503,8 @@ class AsyncWebCrawler:
             tables = media.pop("tables", [])
             links = result.links.model_dump()
             metadata = result.metadata
+            
+        fit_html = preprocess_html_for_schema(html_content=html, text_threshold= 500, max_size= 300_000)
 
         ################################
         # Generate Markdown            #
@@ -519,7 +521,7 @@ class AsyncWebCrawler:
         html_source_selector = {
             "raw_html": lambda: html,  # The original raw HTML
             "cleaned_html": lambda: cleaned_html,  # The HTML after scraping strategy
-            "fit_html": lambda: preprocess_html_for_schema(html_content=html),  # Preprocessed raw HTML
+            "fit_html": lambda: fit_html,  # The HTML after preprocessing for schema
         }
 
         markdown_input_html = cleaned_html  # Default to cleaned_html
@@ -593,6 +595,7 @@ class AsyncWebCrawler:
             content = {
                 "markdown": markdown_result.raw_markdown,
                 "html": html,
+                "fit_html": fit_html,
                 "cleaned_html": cleaned_html,
                 "fit_markdown": markdown_result.fit_markdown,
             }.get(content_format, markdown_result.raw_markdown)
@@ -600,7 +603,7 @@ class AsyncWebCrawler:
             # Use IdentityChunking for HTML input, otherwise use provided chunking strategy
             chunking = (
                 IdentityChunking()
-                if content_format in ["html", "cleaned_html"]
+                if content_format in ["html", "cleaned_html", "fit_html"]
                 else config.chunking_strategy
             )
             sections = chunking.chunk(content)
@@ -624,6 +627,7 @@ class AsyncWebCrawler:
         return CrawlResult(
             url=url,
             html=html,
+            fit_html=fit_html,
             cleaned_html=cleaned_html,
             markdown=markdown_result,
             media=media,