Function parse_math_statements 

pub fn parse_math_statements(code: &str) -> Vec<String>

Parse math code into complete statements.

Handles both Coq-style (period-terminated) and Literate syntax (block-based):

• ## To ... blocks: collect header + all indented lines until non-indented line
• A X is either: blocks: collect header + indented variants
• Traditional commands: accumulate until period-terminator