Function validate_regex_pattern 

pub fn validate_regex_pattern(pattern: &str) -> Result<(), String>

Validates a regex pattern to prevent ReDoS attacks

Security Checks

• Length limits (max 1,000 characters)
• Detects nested quantifiers that could cause ReDoS
• Validates that regex can be compiled
• Warns about potentially dangerous patterns

Arguments

• pattern - User-provided regex pattern

Returns

• Ok(()) if pattern is valid and safe
• Err(String) if pattern is dangerous or invalid