feat: add navigation link to history tab in HistoryPreview

- Add subtle 'View all history →' link at bottom of HistoryPreview component
- Link navigates to history tab using existing switchTab message system
- Styled with VSCode theme variables for consistent appearance
- Improves accessibility to history tab now that it's behind overflow menu

Author: roomote

webview-ui/src/components/history/HistoryPreview.tsx

@@ -1,18 +1,30 @@
 import { memo } from "react"
 
+import { vscode } from "@/utils/vscode"
 import { useTaskSearch } from "./useTaskSearch"
 import TaskItem from "./TaskItem"
 
 const HistoryPreview = () => {
 	const { tasks } = useTaskSearch()
 
+	const handleViewAllHistory = () => {
+		vscode.postMessage({ type: "switchTab", tab: "history" })
+	}
+
 	return (
 		<div className="flex flex-col gap-3">
 			{tasks.length !== 0 && (
 				<>
 					{tasks.slice(0, 3).map((item) => (
 						<TaskItem key={item.id} item={item} variant="compact" />
 					))}
+					<div className="flex justify-center mt-2">
+						<button
+							onClick={handleViewAllHistory}
+							className="text-vscode-descriptionForeground hover:text-vscode-foreground text-sm cursor-pointer transition-colors duration-200 flex items-center gap-1">
+							View all history →
+						</button>
+					</div>
 				</>
 			)}
 		</div>