agent-v0.3.0

Added

• Versioned install layout: host installs now land under /opt/grapheon/agent/releases/<version>/ with /opt/grapheon/agent/current as the active symlink target
• Lifecycle helper scripts: added upgrade-passive-agent.sh, rollback-passive-agent.sh, and uninstall-passive-agent.sh for release-based host management
• Rollback test coverage: packaging tests now verify versioned installs and rollback of the active current symlink using a fake systemctl
• Artifact verification metadata: the release workflow now uploads grapheon-agent-vX.Y.Z.tar.gz.sha256 alongside the tarball

Changed

• install-passive-agent.sh now installs a versioned release directory and updates the stable current symlink instead of overwriting a single in-place runtime path
• The shipped systemd service now executes /opt/grapheon/agent/current/grapheon_agent.py so upgrades and rollbacks do not require editing the unit file
• Agent packaging docs now cover release verification, upgrade, rollback, uninstall, and the versioned install layout