Module options 

Unified compile options.

Replaces the historical mix of compile(), compile_with_precision(), compile_with_options() with a single Backend::compile(graph, &options). New compile-time knobs can be added to CompileOptions without changing the trait — backends just read what they care about.

Builder-pattern API for ergonomics:

let opts = CompileOptions::new()
    .precision(Precision::F16)
    .policy(PrecisionPolicy::AutoMixed)
    .with_dce(true)
    .with_constant_folding(true);

Structs

CompileOptions

All knobs the compile pipeline understands. Add new fields here rather than introducing new compile entry points.