feat(desktop): polish desktop shell and shared WebUI surfaces (#4195)

* feat(desktop): add native host scaffold

* feat(webui): track turns and usage in gateway

* feat(webui): polish desktop chat experience

* feat(apps): add ArcGIS and Joplin logos

* feat(desktop): polish shell and shared surfaces

* fix(webui): avoid preview chips for glob references

* test: align CI expectations for token fallback

* feat(webui): preview prompt rail entries

* feat(webui): add prompt navigator drawer

* style(webui): refine prompt navigator placement

* style(webui): align prompt navigator with header actions

* style(webui): simplify prompt navigator header

* refactor(webui): clean thread resource refresh

* feat(desktop): add native reply notifications

* fix(webui): preserve desktop restart and replay state

* fix(desktop): harden gateway proxy startup

* fix(web): fall back when readability is unavailable

* fix(desktop): hide window instead of closing on macos

* fix(webui): unify desktop header actions

* fix(webui): simplify prompt history rows

* fix(desktop): log notification delivery failures

* chore(desktop): clean source package artifacts

* fix(cron): support one-time relative reminders

* fix(webui): reveal scroll button in place

* Revert "fix(cron): support one-time relative reminders"

This reverts commit 4c4661da120a3c7283e0768412bae48604e7390b.

* refactor(webui): extract token usage heatmap

* docs(desktop): clarify contributor guides

---------

Co-authored-by: chengyongru <2755839590@qq.com>

webui/src/components/thread/ThreadMessages.tsx

@@ -14,6 +14,7 @@ interface ThreadMessagesProps {
   onLoadEarlier?: () => void;
   cliApps?: CliAppInfo[];
   mcpPresets?: McpPresetInfo[];
+  onOpenFilePreview?: (path: string) => void;
 }
 
 export type DisplayUnit = TurnUnit;
@@ -33,8 +34,13 @@ export function isFinalAssistantSliceBeforeNextUser(
   return true;
 }
 
-export function buildDisplayUnits(messages: UIMessage[]): DisplayUnit[] {
-  return normalizeActivityTimeline(messages);
+export function buildDisplayUnits(
+  messages: UIMessage[],
+  isStreaming = false,
+): DisplayUnit[] {
+  return normalizeActivityTimeline(messages, {
+    preserveTrailingActivity: isStreaming,
+  });
 }
 
 export function assistantCopyFlags(units: DisplayUnit[]): boolean[] {
@@ -61,9 +67,10 @@ export function ThreadMessages({
   onLoadEarlier,
   cliApps = [],
   mcpPresets = [],
+  onOpenFilePreview,
 }: ThreadMessagesProps) {
   const { t } = useTranslation();
-  const units = useMemo(() => buildDisplayUnits(messages), [messages]);
+  const units = useMemo(() => buildDisplayUnits(messages, isStreaming), [isStreaming, messages]);
   const copyFlags = useMemo(() => assistantCopyFlags(units), [units]);
   const liveActivityClusterIndices = useMemo(
     () => isStreaming ? currentActivityClusterIndices(units) : new Set<number>(),
@@ -117,6 +124,7 @@ export function ThreadMessages({
                 turnLatencyMs={unit.turnLatencyMs}
                 cliApps={cliApps}
                 mcpPresets={mcpPresets}
+                onOpenFilePreview={onOpenFilePreview}
               />
             ) : (
               <MessageBubble
@@ -128,6 +136,7 @@ export function ThreadMessages({
                 }
                 cliApps={cliApps}
                 mcpPresets={mcpPresets}
+                onOpenFilePreview={onOpenFilePreview}
               />
             )}
           </div>