Offline Sync Queue 2D: Write Coalescing & Payload Compaction

2D companion to the 3D offline-first mobile sync model: the same local-store-as-source-of-truth architecture, rendered as a flat grid of record tiles instead of a 3D scene. Editing while "offline" appends entries to a raw mutation log, and a last-write-wins coalescing step — a plain Map keyed by record id — collapses repeat edits to the same record down to one before the sync round trip. Tune the active record count and offline edit rate to control how often edits collide on the same key, toggle coalescing on or off to compare raw versus compacted payload size, and watch the sync packets travel down the device-to-server lane at a rate set by the bandwidth slider while live readouts track queue length, payload bytes, compression ratio and estimated sync time.