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.