- sync: timestamps and tombstones in the shared file are clipped to the
local clock, and an edit wins a tie with a deletion, so a forged
future-dated record can no longer override every later local change
(or keep deleting a re-created profile) for as long as the forged date.
- write_private: the temp file is created O_EXCL under a random name, so a
symlink pre-placed in a shared folder can't be followed or overwritten.
- Vault/keychain reads return Zeroizing<String>; has_sync_password is
cached for a few seconds instead of fetching the real value every frame.
- generate_ssh_key creates a missing ~/.ssh as 0700.
- Honest wording: encrypted exports and the sync file carry login-script
values; the audit entry, the Settings hint and the docs now say so.