package_hash fed each package-relative path to the digest with
to_string_lossy, so a walked path hashed as `web\index.html` on Windows
and `web/index.html` elsewhere. The same package had two digests: a
market index built on Linux failed verification on Windows, and a
package signed on one OS did not verify on another.
Join path components with `/` before hashing. Digests on macOS and
Linux are unchanged byte for byte; installed plugins keep their recorded
.package-hash, and a recomputed digest is accepted as a silent update by
the grant ledger, so existing Windows installs are not re-prompted.
Closes#1258
l0ng-ai
6d55eb4aa9