SubMiner/changes/launcher-sync-command.md

type: added area: launcher

• Added subminer sync <host> to merge immersion stats and watch history between two machines over SSH. Each side snapshots its database (VACUUM INTO), snapshots are exchanged with scp, and each machine merges the other's data as an insert-only union keyed on session UUIDs / video keys / series title keys, so re-syncing is idempotent and nothing is double-counted. Lifetime totals and daily/monthly rollups are updated incrementally (history older than the session retention window is preserved); remote-only historical rollups are copied only when they do not conflict with retained local session history. subminer sync --snapshot <file> and subminer sync --merge <file> expose the underlying steps for manual transfers. The command refuses to run while the stats daemon or an mpv session is active (--force overrides), keeps that guard in place through local/remote merges, reports remote stderr on failures, and aborts on stats schema version mismatches.