feat(ext): add chat history

packages/extension/src/entrypoints/sidepanel/components/HistoryDetail.tsx

@@ -0,0 +1,51 @@
+import { ArrowLeft } from 'lucide-react'
+import { useEffect, useState } from 'react'
+
+import { Button } from '@/components/ui/button'
+import { type SessionRecord, getSession } from '@/lib/db'
+
+import { EventCard } from './cards'
+
+export function HistoryDetail({ sessionId, onBack }: { sessionId: string; onBack: () => void }) {
+	const [session, setSession] = useState<SessionRecord | null>(null)
+
+	useEffect(() => {
+		getSession(sessionId).then((s) => setSession(s ?? null))
+	}, [sessionId])
+
+	if (!session) {
+		return (
+			<div className="flex items-center justify-center h-screen text-xs text-muted-foreground">
+				Loading...
+			</div>
+		)
+	}
+
+	return (
+		<div className="flex flex-col h-screen bg-background">
+			{/* Header */}
+			<header className="flex items-center gap-2 border-b px-3 py-2">
+				<Button variant="ghost" size="icon-sm" onClick={onBack} className="cursor-pointer">
+					<ArrowLeft className="size-3.5" />
+				</Button>
+				<span className="text-sm font-medium truncate">History</span>
+			</header>
+
+			{/* Task */}
+			<div className="border-b px-3 py-2 bg-muted/30">
+				<div className="text-[10px] text-muted-foreground uppercase tracking-wide">Task</div>
+				<div className="text-xs font-medium" title={session.task}>
+					{session.task}
+				</div>
+			</div>
+
+			{/* Events (read-only) */}
+			<div className="flex-1 overflow-y-auto p-3 space-y-2">
+				{session.history.map((event, index) => (
+					// eslint-disable-next-line react-x/no-array-index-key
+					<EventCard key={index} event={event} />
+				))}
+			</div>
+		</div>
+	)
+}