Merge pull request #10 from orientpine/feat/linux-systemd-user-timer

feat(linux): prefer systemd user timer for suspend/reboot catch-up

refactor: remove multi-account and --force, simplify to single-account sync

fix: run the Windows scheduler through a hidden script host

docs: mark multi-account as experimental

docs: clarify the recommended multi-account login flow

fix: prevent multi-account overwrite on switch and reject unknown commands

fix: suppress normal output in non-TTY (LaunchAgent/cron) to prevent macOS notifications

feat: add --version flag to bash and PowerShell scripts

docs: remove verbose How It Works section

docs: reposition as the cross-platform multi-account credential sync tool

docs: improve README readability with collapsible sections and visual separation

docs: clarify 1.3+ scope and simplify plugin guidance

docs: fix inaccurate line count, remove outdated built-in references, add alternative plugins

fix: self-heal stale active account state