attachment_engine_web 0.0.1-dev.1

Web implementation of attachment_engine providing Web Share API, OPFS storage, fetch downloads, and HTML5 video/audio playback.

0.0.1-dev.1

• Initial development release: share (shareText, via the Web Share API) and open-externally (window.open) — via raw dart:js_interop (a Dart SDK core library, not even a pub package).
• Added paths (getApplicationSupportDirectory/ getApplicationCacheDirectory) via the Origin Private File System (OPFS, navigator.storage.getDirectory()), returning a stable logical key rather than a real OS path — see README for details.
• Added download (startDownload/resumeDownload/cancelDownload/ downloadEvents) via fetch() streamed chunk-by-chunk into OPFS, with AbortController-backed cancellation and the same {downloadId, type, received, total, path, message} event shape used by the other platforms.
• Added video/audio playback (video*/audio*) via real <video>/<audio> elements driven with dart:js_interop, with the video surface embedded through dart:ui_web's platformViewRegistry.registerViewFactory, emitting the same {state, positionMs, durationMs, width, height} (video) / {state, positionMs, durationMs} (audio) event shape as iOS/Android.
• shareFile, PDF native rendering, and embedded webview are still not implemented — see README for why (PDF.js integration was investigated and deliberately deferred as a documented follow-up rather than forced in; webview is out of scope for every platform in this contract).