fix: handle nested brackets and parentheses in LINK_PATTERN regex

The previous regex [^\]]+ stopped at the first ] which broke
markdown links containing embedded images like:

The new pattern allows one level of nested [...] in the link text
and one level of nested (...) in the URL, correctly handling:
- Embedded images in link text
- Wikipedia-style URLs with parentheses

Fixes #711

crawl4ai/markdown_generation_strategy.py

@@ -8,7 +8,7 @@ import re
 from urllib.parse import urljoin
 
 # Pre-compile the regex pattern
-LINK_PATTERN = re.compile(r'!?\[([^\]]+)\]\(([^)]+?)(?:\s+"([^"]*)")?\)')
+LINK_PATTERN = re.compile(r'!?\[((?:[^\[\]]|\[(?:[^\[\]]|\[[^\]]*\])*\])*)\]\(((?:[^()\s]|\([^()]*\))*)(?:\s+"([^"]*)")?\)')
 
 
 def fast_urljoin(base: str, url: str) -> str: