Remove the macOS keychain ACL rewrite that demanded the login password.

0.1.27 narrowed the prompt from every credential read to once per item per
process, which left the cause standing: SecKeychainItemSetAccess is a
privileged write and macOS gates it behind the password on every call, while
reading through an access list that already admits the app is silent. The
rewrite is gone rather than deduplicated. Existing credentials are untouched
and need no re-entry.