Function resolve 

pub fn resolve(rel: &str) -> String

Resolve a default (CWD-relative) asset path. If it doesn’t exist relative to the current directory, try next to the executable and one level above it (following symlinks — the layout scripts/install/install.sh produces: /usr/local/bin/docling-rs → /usr/local/docling.rs/bin/docling-rs with .models/ and .pdfium/ in /usr/local/docling.rs). Returns rel unchanged when nothing exists anywhere, so callers’ error messages keep the familiar path. Explicit env overrides never reach this.