Function brace_up_single_statement_blocks 

pub(crate) fn brace_up_single_statement_blocks(src: &str) -> String

Wrap single-statement if/while/for bodies in { ... }. WGSL requires braces on every conditional/loop body; HLSL doesn’t, and a lot of MD2 preset code uses the brace-less form (if (cond) ret.z -= 0.5;).

We walk the source, find each if / while / for keyword, balance the condition parens, and if the next non-whitespace character isn’t {, we wrap from there to the next top-level ; (tracking parens to skip nested calls) in braces.