Preserve Linux archive failures and require current query-role runtime

docs/BUILDING.md

@@ -154,6 +154,14 @@ same normalized TAR members, file checksums and executable modes. XZ uses the
 standard library's preset 6. The extraction smoke accepts either format. A
 smaller download does not change runtime behavior or ABI requirements.
 
+Always use the current normal runtime directory, not a copied historical
+desktop staging cache. A valid old checksum inventory alone does not prove
+compatibility with the current foreground query protocol. Before packaging,
+exercise actual query-role inference with the selected worker; then run the
+full extracted archive smoke. A legacy worker lacking `--role query` can build
+document vectors while failing foreground search. The archive smoke retains
+captured CLI error output when a command exits unsuccessfully.
+
 The optional Linux missing-loader check requires explicit root execution and
 util-linux mount namespaces/chroot. It never escalates privileges and verifies
 a private namespace before creating an isolated filesystem: