Bring the 1.0.0 release notes up to date with the release-hardening work
completed after the initial metadata pass: worker heartbeat tracking,
incomplete snapshot cleanup, review resolution, SSH key management hardening,
purged snapshot audit history, and the in-app changelog page.
Refs #8
Refs #10
Refs #11
Refs #16
Refs #19
Refs #20
Add the initial 1.0.0 changelog, bump the package/application version,
and expose the release version through `pobsync --version`.
Cover the version output in the console entrypoint tests.
