Function classify_host_error 

pub fn classify_host_error(e: &Error, no_skip: bool) -> HostClass

Classify a test-body error against the host-insufficiency taxonomy.

no_skip is KTSTR_NO_SKIP_MODE — passed in (not read from the environment here) so the function stays pure and unit-testable without env mutation. Each caller reads the env once (result_to_exit_code for dispatch; the generated body for the macro) and threads it in.

The guard ORDER and the per-class skip/fail policy below are the single source of truth shared by both consumers. expect_err is deliberately NOT a parameter: a host-class outcome is invariant under it (a skip stays a skip, a hard fail stays a hard fail) — expect_err is a test-outcome concern each consumer handles after a HostClass::NotHostClass result. The reason strings reconstruct the exact banners the two sites emitted before this was extracted (minus the prefix, which the consumer adds).