Add Files... and Upload Folder... read every picked file in one go and
rejected on the first file the browser couldn't read; the Media
Browser dropped that rejection, so nothing was added and nothing said
why. Each file is now read on its own: the readable ones are added and
the status bar names the unreadable ones with the browser's reason and
suggests picking them again. Cancelling the picker is not reported.
Test: apps/effectcraft-web/tests/page.mjs (Node, fake DOM).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Viewer frames render in long-lived Web Workers holding a project replica
(engine::remote: structural JSON diff/patch, Mirror, FrameServer); the
frame cache hands jobs to a RemoteFrames renderer (UI-thread fallback).
Roto Brush propagation runs in a job worker and streams segmentations
back (FrameSeg binary form), relayed to frame workers. Control-channel
wait:true commands whose job is offloaded reply when it ends. The Media
Browser browses a pluggable Browser: the file system on the desktop;
browser storage and File System Access folders on the web.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
