Summary

• Add builder pattern to complex structs: VM, PrintTracer, Compiler, Parser
• Add fluent builder to config structs: Config, FuelLimits
• Add semantic constructors to bytecode structs: TypeDef, Entrypoint, Call, Return, Trampoline, etc.
• Make struct fields pub(crate) with getters for external access

Why

Enables composable struct construction while enforcing encapsulation. External consumers use builders/constructors; internal code can access fields directly via pub(crate).