fix: resolve checkpoint menu popover overflow

- Updated PopoverContent to use auto-sizing (w-auto min-w-max) instead of fixed width
- Added whitespace-nowrap to buttons to prevent text wrapping
- Maintains center alignment while fixing overflow of 'View Changes Since This Checkpoint' text

Author: daniel-lxs

webview-ui/src/components/chat/checkpoints/CheckpointMenu.tsx

@@ -173,10 +173,11 @@ export const CheckpointMenu = ({ ts, commitHash, checkpoint, onOpenChange }: Che
 						</Button>
 					</PopoverTrigger>
 				</StandardTooltip>
-				<PopoverContent align="end" container={portalContainer}>
+				<PopoverContent align="end" container={portalContainer} className="w-auto min-w-max">
 					<div className="flex flex-col gap-2">
 						<Button
 							variant="secondary"
+							className="whitespace-nowrap"
 							onClick={() => {
 								onDiffFromInit()
 								setMoreOpen(false)
@@ -186,6 +187,7 @@ export const CheckpointMenu = ({ ts, commitHash, checkpoint, onOpenChange }: Che
 						</Button>
 						<Button
 							variant="secondary"
+							className="whitespace-nowrap"
 							onClick={() => {
 								onDiffWithCurrent()
 								setMoreOpen(false)