Shared inventory + manifest plumbing for the wolfram-export-* runtime
crates.
Hosts the [ExportEntry] enum (the unified inventory entry type used by
all three modes — Native, Wstp, Wxf), the inventory::collect! declaration,
and the [exported_library_functions_association] builder that produces
the WL Association[name -> LibraryFunctionLoad[...], ...] Expr used by
both the WSTP-mode generate_loader! runtime path and the WXF-mode
build-time manifest path.
The two transports share this one Expr-producing function — only the wire format at the boundary differs.