Refresh PR #2258 onto master at 5427cbcc19 so the session-log export fixes are evaluated and mergeable against the current repository.\n\nPreserve master's SDK-toolchain removal, client theme bootstrap, and Python finish-reason changes intact. The only textual overlap is the generated config-catalog pairing record: both English and Chinese catalogs merge cleanly with the PR's compression setting and master's package moves, so regenerate that sidecar from the merged owners instead of choosing either stale hash.
Single-click original preview in the composer rail and chat history; remove
control inside the thumbnail, revealed on hover/focus (always on touch);
hidden-scrollbar rail overflow paged by edge arrows with wheel panning and
end-reveal on add; image-intake rejections and prompt failures announce as a
transient top-center toast instead of inline strips.
The attachment atoms move to a new zero-cordis package
@deepseek-ai/dsh-client-ui-attachment (rail, message gallery, lightbox),
seeded as a platform module; the toast is a ui-primitives atom. Strings
arrive as label props bridged from the conversation dictionary.
Session-log ZIP entries always used DEFLATE level 6 even though compression level is a deployment tradeoff: CPU-constrained hosts may prefer low latency while bandwidth-constrained hosts may prefer smaller archives. A hardcoded level also violated the repository rule that deployment-varying plugin choices live in validated Config.
Add sessionExportCompressionLevel to ApiProxyService.Config as an integer 0-9 with default 6, resolve the same default once for direct createApiProxy callers, and pass the required level into the streaming module. Tests prove schema defaulting and rejection as well as a level-0 versus level-9 archive-size difference with identical extracted content. The generated config catalog, bilingual gateway README, and feature note document the knob and its tradeoff.
The ZIP loop checked desiredSize only after a push and responded to an overfull queue with setTimeout(0). A timer turn does not mean the consumer drained anything, so a slow or disconnected client still allowed the producer to enqueue the complete compressed archive while later artifact and attachment reads ran eagerly.
Give the ReadableStream a 64 KiB byte queuing strategy and block the single producer on a pull-released capacity gate whenever desiredSize is non-positive. Cancellation wakes that gate through the existing producer signal; synchronous fflate output is therefore bounded to the queue high-water mark plus one input push. A regression test exhausts timer turns without consuming and proves the next media entry remains unread until response pulling begins, and the bilingual contracts now describe the real bound.
Only the root raw-artifact read received the request signal. Lineage discovery and descendant reads could continue after disconnect, response-body cancellation did not stop the producer, and the root error boundary converted an abort rejection into an ordinary HTTP 500.
Combine request and response-consumer cancellation into the ZIP producer signal, forward it through every cancellable read, check it around the attachment seam, and terminate fflate exactly once when production stops. The pre-stream boundary now rethrows the original abort instead of translating it. Regression tests cover signal propagation, exact cancellation identity at the HTTP boundary, and a reader cancellation interrupting an in-flight descendant read; the bilingual host contract records these lifecycle semantics.
The exporter read persistence artifacts directly even when the requested root or a descendant was still live. Buffered session events could therefore be omitted from a successful download, so the advertised verbatim-artifact guarantee described storage accurately but captured an arbitrarily stale durability boundary.
Resolve each id against SessionStore and cross its authoritative flush barrier immediately before readRaw. Cold sessions remain a no-op, while live roots and descendants are made durable independently; this intentionally yields a per-session read-boundary snapshot rather than claiming an atomic lineage snapshot. A host-path regression test proves both artifacts change from stale to durable only through flush, and the bilingual host contract and Agent Note document the boundary.
ZiyaZhang