Function build_pipeline_from_wgsl 

fn build_pipeline_from_wgsl(
    device: &Device,
    pipeline_layout: &PipelineLayout,
    target_format: TextureFormat,
    source: &str,
    label: &str,
) -> Result<RenderPipeline>

Build a comp-pass RenderPipeline from a fully-formed WGSL source string.

Used both for the default shader (built once at startup) and the user shader (rebuilt on every preset load). The vertex/fragment entry-point names are fixed by convention (vs_main/fs_main) — the user-shader wrapper in onedrop-codegen produces them, and the default comp.wgsl matches.