I'm creating an extremely difficult challenge incorporating multiple advanced regex concepts:
1. IPv6 addresses with various compression formats and case sensitivity
2. Complex password patterns with specific requirements (uppercase, lowercase, digits, special chars)
3. JWT tokens with specific structure verification
4. Credit card numbers with different formats (with/without spaces/dashes) and validation patterns
5. Currency values with multiple formats and optional decimals
6. Markdown code bl... (truncated)