feat: show expandable tool call details in chat activity panel

Thread toolArguments from the sidecar through shared contracts, main-process pipeline, and into the renderer. Add ToolCallDetailPanel with inline summaries (command, path, pattern, etc.) and expandable argument details for every tool-call event in the activity timeline.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/renderer/components/chat/TurnActivityPanel.tsx

@@ -15,6 +15,7 @@ import {
 
 import { useElapsedTimer } from '@renderer/hooks/useElapsedTimer';
 import { FileChangePreview } from '@renderer/components/chat/FileChangePreview';
+import { ToolCallDetailPanel } from '@renderer/components/chat/ToolCallDetailPanel';
 import { RunChangeSummaryCard } from '@renderer/components/chat/RunChangeSummaryCard';
 import { formatEventLabel, truncateContent, filterEventsByAgent, summarizeActivity, type ActivitySummary } from '@renderer/lib/runTimelineFormatting';
 import type { ChatMessageRecord } from '@shared/domain/session';
@@ -186,6 +187,11 @@ function ActivityTimelineEventRow({ event }: { event: RunTimelineEventRecord })
           </p>
         )}
 
+        {/* Tool call argument details */}
+        {event.kind === 'tool-call' && (
+          <ToolCallDetailPanel toolName={event.toolName} toolArguments={event.toolArguments} />
+        )}
+
         {/* File change preview for tool-call events */}
         {event.kind === 'tool-call' && event.fileChanges && event.fileChanges.length > 0 && (
           <div className="mt-1">