Function extract_code_references 

pub fn extract_code_references(text: &str) -> Vec<String>

Extract code references from free-form text for use in auto-linking.

Recognizes:

• CamelCase identifiers (likely type/class names): ProcessRequest, HashMap
• Backtick-wrapped code: content from `…`
• Function-like patterns: word() or word::path
• Short file paths: patterns like src/foo.rs, lib/bar.py

Returns deduplicated references suitable for matching against graph node labels.