Sync and the mutation queue

Every change is an atomic mutation through an asynchronous queue.

• verified 😍 Saves automatically, with no save button /help/get-started
• verified The same account on several devicespersona: twins, persona: keeping /features/
• verified 😍 Every mutation is queued client-side before it is sent pandoPando axiom 4.
• verified 😍 A mutation applies in the UI immediately pandoPando axiom: latency zero.
• tested A rejected mutation is rolled back and the reason is shown pandoPando axiom: no silent success.test/queue.test.js, test/e2e/concurrent.mjs
• verified Mutations apply in the order they were made, per device pandopersona: twins
• verified The queue survives going offline and drains on reconnect pandopersona: queue
• tested Replaying a mutation twice has the same effect as once pandotest/queue.test.js, test/e2e/concurrent.mjs
• verified Concurrent edits converge deterministically pandopersona: again