Implement bundled multi-camera --start-frame semantics as synced-group\nindices from the common synced start, inclusive with --end-frame.\n\nUpdate zed_svo_to_mcap to skip synced groups before writing, keep\nsingle-camera raw SVO frame semantics unchanged, and adjust exact\nprogress totals for selected bundled windows.\n\nReplace the expensive bundled exact pre-count path with approximate\ntime-window progress when --end-frame is not set, and update the\nshared TTY progress bar helper to support fraction-based rendering.\n\nExpose --start-frame in the batch MCAP wrapper and document the\nbundled frame-window semantics and approximate progress behavior in\nthe README.
crosstyan
7808b89a03