Clickable Activity Summary — no more silent clicks
Clicking the "Done · N tool calls" row under an assistant message now reliably opens the activity panel for that message. The summary's onClick was gated on data.sourceKey, but MessageContent was building activityData without one — so the click silently no-op'd. activityKey is now threaded through MessageContent into sourceKey, and the chevron also rotates when that message's panel is open so the state is visible at a glance.
File Previews Scoped to the Active Workspace
PDF / DOCX / PPTX / XLSX renderers now pass the active workspace with every CONTENT_BINARY request, so a file opens against the session where it actually lives — no more wrong-context fetches when you switch workspaces with artifacts still on screen. PDFs additionally get proper CJK and standard-font rendering: the renderer now supplies cMapUrl and standardFontDataUrl (Chinese, Japanese, Korean characters stop falling back to boxes), and memoizes the file prop so resizing the panel no longer re-fetches the document.
Mutually Exclusive Side Panels
Opening the Workspace panel now closes Activity, Artifact, and PlanReview — and vice versa — so panels no longer stack and cover each other. The chat header's workspace toggle now decides based on the panel's actually-visible state rather than raw isOpen, since an overlay panel can sit on top of it. An opaque surface-chat backdrop behind the sidebar column also kills the brief flashes that used to show up during panel open/close animations.
Sidebar Theming & Motion
New --sidebar-translucent-bg token replaces the ad-hoc /20 alpha everywhere the main Sidebar and the new SettingsSidebar were tinted — 88% alpha in light mode, 20% in dark, derived from your chosen background via the appearance injector. Sidebar collapse and expand now use a spring transition instead of a tween, so it opens and closes with the same rhythm as the Activity / Artifact / PlanReview panels. Smaller polish: explicit color tokens on the chat send button for a legible dark-mode disabled state, the context-indicator tooltip is pointer-events-none so it can't trap the cursor, and the activity panel drops its left border and vertical timeline connector for a cleaner look.
Upgrading from 1.1.1
Users already on 1.1.1 will receive this update automatically through the in-app updater within a few hours, or can trigger it immediately via Help → Check for Updates. No migrations, no reconfiguration — everything carries over. If you were hitting "click activity summary does nothing" or garbled CJK characters in PDF previews, those are the exact paths this release fixes.