pub const NO_SITE: u32 = u32::MAX; // 4_294_967_295u32Expand description
site_id sentinel meaning “no source location” — runtime-internal
raises (query-side undefined goals) and any binary built without
provenance. The error message gets no at file:line:col suffix.
ABI contract: MUST equal plg_compiler::codegen::NO_SITE (codegen emits
this value as the site_id arg). Separate consts in separate crates;
each pins == u32::MAX in a unit test to flag a one-sided renumber.