Team mode's second half. A board-made move already commits itself (18);
now that commit publishes, every board pulls on a beat, and a card two
boards move at once resolves the way git resolves everything else — the
push race is the concurrency control.
- core/sync.py: push is event-driven (a new state.COMMIT_HOOKS registry
fires it from taskfiles, so taskfiles stays left of everything that
reacts to it); pull is a beat that fast-forwards, or replays this
board's own commits on top when the two diverged. A replay that
conflicts on a task file drops the local move — origin is the
linearizer — and toasts who took the card.
- The piggyback guard stands in front of every push and every replay:
each local-ahead commit on main must be `board: `-prefixed, so a
human's unpushed work is never published as a side effect of a card
moving. Uncommitted changes, a checkout off main and an unreachable
origin all stall or degrade rather than risk anything, each narrated
once instead of once per beat.
- watch.py names the commit author instead of "disk" for moves a pull
brought, via the arrivals sync files for it; its narration moved out
of the loop into narrate() so it can be tested directly.
- The board grows a sync chip that appears only when sync stops
converging, and the SSE stream grows a toast type so the server can
say something to the person, not just to the ticker.
Gate off (the default) means no fetch, no push, no thread, no change.
Verified with tests/test_boards_sync.py: two real clones of a real bare
upstream race each other through every case above.
istos
9d98e2c55a