Function generate_bindings 

pub fn generate_bindings(class_def: &ClassDef) -> GeneratedBindings

Generate SpiderMonkey binding code from a parsed class definition.

Rejects class names that would produce invalid Rust identifiers (e.g. <Class>_constructor) before emitting any code, so malformed inputs surface as a clear error instead of an opaque compile failure in the generated module.

@trace REQ-ENG-002 [entity:CodegenBackend]