feat: improve accessibility, security & user interaction in notifications and setup

- Replaced `div` with `button` elements in `NotificationHandler` for better semantics and accessibility.
- Added conditional QR Code reveal in 2FA setup with `blur` effect for enhanced security and user control.
- Enhanced messages layout for responsiveness on smaller screens with dynamic chat/sidebar toggling.
- Simplified legacy prop handling in `ShareDialog`.

frontend/src/app/(dashboard)/messages/page.tsx

@@ -2,7 +2,7 @@
 
 import { formatDistanceToNow } from "date-fns";
 import { fr } from "date-fns/locale";
-import { Search, Send, UserPlus, X } from "lucide-react";
+import { ArrowLeft, Search, Send, UserPlus, X } from "lucide-react";
 import Link from "next/link";
 import { useRouter, useSearchParams } from "next/navigation";
 import * as React from "react";
@@ -238,7 +238,11 @@ export default function MessagesPage() {
 	return (
 		<div className="h-[calc(100vh-4rem)] flex overflow-hidden bg-white dark:bg-zinc-950">
 			{/* Sidebar - Liste des conversations */}
-			<div className="w-80 border-r flex flex-col">
+			<div
+				className={`w-full md:w-80 border-r flex flex-col ${
+					activeConv ? "hidden md:flex" : "flex"
+				}`}
+			>
 				<div className="p-4 border-b">
 					<div className="flex items-center justify-between mb-4">
 						<h2 className="text-xl font-bold">Messages</h2>
@@ -378,14 +382,26 @@ export default function MessagesPage() {
 			</div>
 
 			{/* Zone de chat */}
-			<div className="flex-1 flex flex-col">
+			<div
+				className={`flex-1 flex flex-col ${
+					!activeConv ? "hidden md:flex" : "flex"
+				}`}
+			>
 				{activeConv ? (
 					<>
 						{/* Header */}
-						<div className="p-4 border-b flex items-center justify-between">
+						<div className="p-4 border-b flex items-center gap-2">
+							<Button
+								variant="ghost"
+								size="icon"
+								className="md:hidden rounded-full"
+								onClick={() => setActiveConv(null)}
+							>
+								<ArrowLeft className="h-5 w-5" />
+							</Button>
 							<Link
 								href={`/user/${activeConv.recipient.username}`}
-								className="flex items-center gap-3 hover:opacity-80 transition-opacity"
+								className="flex-1 flex items-center gap-3 hover:opacity-80 transition-opacity"
 							>
 								<Avatar className="h-8 w-8">
 									<AvatarImage src={activeConv.recipient.avatarUrl} />

frontend/src/components/notification-handler.tsx

@@ -30,10 +30,9 @@ export function NotificationHandler() {
 
 			toast.custom(
 				(t) => (
-					<div
-						role="button"
-						tabIndex={0}
-						className="flex items-start gap-3 bg-white dark:bg-zinc-900 p-4 rounded-xl shadow-lg border border-zinc-200 dark:border-zinc-800 w-full max-w-sm cursor-pointer hover:bg-zinc-50 dark:hover:bg-zinc-800 transition-colors"
+					<button
+						type="button"
+						className="flex items-start gap-3 bg-white dark:bg-zinc-900 p-4 rounded-xl shadow-lg border border-zinc-200 dark:border-zinc-800 w-full max-w-sm cursor-pointer hover:bg-zinc-50 dark:hover:bg-zinc-800 transition-colors text-left"
 						onClick={() => {
 							toast.dismiss(t);
 							if (data.type === "message") {
@@ -42,16 +41,6 @@ export function NotificationHandler() {
 								router.push(`/meme/${data.contentId}`);
 							}
 						}}
-						onKeyDown={(e) => {
-							if (e.key === "Enter" || e.key === " ") {
-								toast.dismiss(t);
-								if (data.type === "message") {
-									router.push("/messages");
-								} else if (data.contentId) {
-									router.push(`/meme/${data.contentId}`);
-								}
-							}
-						}}
 					>
 						<div className="bg-primary/10 p-2 rounded-full shrink-0">
 							{data.type === "comment" && (
@@ -71,15 +60,15 @@ export function NotificationHandler() {
 						</div>
 						<button
 							type="button"
+							className="text-muted-foreground hover:text-foreground p-1 rounded-full hover:bg-zinc-100 dark:hover:bg-zinc-800 transition-colors"
 							onClick={(e) => {
 								e.stopPropagation();
 								toast.dismiss(t);
 							}}
-							className="text-muted-foreground hover:text-foreground"
 						>
 							<Bell className="h-3 w-3" />
 						</button>
-					</div>
+					</button>
 				),
 				{
 					duration: 5000,
@@ -91,20 +80,23 @@ export function NotificationHandler() {
 		socket.on("notification", handleNotification);
 
 		// Aussi pour les nouveaux messages (si on veut un toast global)
-		socket.on("new_message", (data: { message: any }) => {
-			if (window.location.pathname !== "/messages") {
-				toast(
-					`Nouveau message de @${data.message.sender?.username || "un membre"}`,
-					{
-						description: data.message.text.substring(0, 50),
-						action: {
-							label: "Voir",
-							onClick: () => router.push("/messages"),
+		socket.on(
+			"new_message",
+			(data: { message: { text: string; sender?: { username: string } } }) => {
+				if (window.location.pathname !== "/messages") {
+					toast(
+						`Nouveau message de @${data.message.sender?.username || "un membre"}`,
+						{
+							description: data.message.text.substring(0, 50),
+							action: {
+								label: "Voir",
+								onClick: () => router.push("/messages"),
+							},
 						},
-					},
-				);
-			}
-		});
+					);
+				}
+			},
+		);
 
 		return () => {
 			socket.off("notification");

frontend/src/components/share-dialog.tsx

@@ -28,9 +28,10 @@ interface ShareDialogProps {
 export function ShareDialog({
 	contentId,
 	contentTitle,
+	contentUrl: _unused, // Support legacy prop
 	open,
 	onOpenChange,
-}: Omit<ShareDialogProps, "contentUrl">) {
+}: ShareDialogProps) {
 	const [searchQuery, setSearchQuery] = React.useState("");
 	const [results, setResults] = React.useState<User[]>([]);
 	const [isLoading, setIsLoading] = React.useState(false);

frontend/src/components/two-factor-setup.tsx

@@ -29,6 +29,7 @@ export function TwoFactorSetup() {
 	const [secret, setSecret] = useState<string | null>(null);
 	const [otpValue, setOtpValue] = useState("");
 	const [isLoading, setIsLoading] = useState(false);
+	const [isRevealed, setIsRevealed] = useState(false);
 
 	const handleSetup = async () => {
 		setIsLoading(true);
@@ -152,24 +153,59 @@ export function TwoFactorSetup() {
 				</CardHeader>
 				<CardContent className="flex flex-col items-center gap-6">
 					{qrCode && (
-						<div className="bg-white p-4 rounded-xl border-4 border-zinc-100">
-							<Image
-								src={qrCode}
-								alt="QR Code 2FA"
-								width={192}
-								height={192}
-								className="w-48 h-48"
-								unoptimized
-							/>
+						<div className="relative group">
+							<div
+								className={`bg-white p-4 rounded-xl border-4 border-zinc-100 transition-all duration-300 ${
+									!isRevealed ? "blur-md select-none" : ""
+								}`}
+							>
+								<Image
+									src={qrCode}
+									alt="QR Code 2FA"
+									width={192}
+									height={192}
+									className="w-48 h-48"
+									unoptimized
+								/>
+							</div>
+							{!isRevealed && (
+								<div className="absolute inset-0 flex items-center justify-center">
+									<Button
+										variant="secondary"
+										size="sm"
+										onClick={() => setIsRevealed(true)}
+										className="shadow-lg"
+									>
+										Afficher le QR Code
+									</Button>
+								</div>
+							)}
 						</div>
 					)}
 					<div className="w-full space-y-2">
 						<p className="text-sm font-medium text-center">
 							Ou entrez ce code manuellement :
 						</p>
-						<code className="block p-2 bg-muted text-center rounded text-xs font-mono break-all">
-							{secret}
-						</code>
+						<div className="relative group">
+							<code
+								className={`block p-2 bg-muted text-center rounded text-xs font-mono break-all transition-all duration-300 ${
+									!isRevealed ? "blur-[3px] select-none" : ""
+								}`}
+							>
+								{secret}
+							</code>
+							{!isRevealed && (
+								<div className="absolute inset-0 flex items-center justify-center">
+									<button
+										type="button"
+										onClick={() => setIsRevealed(true)}
+										className="text-[10px] font-bold uppercase tracking-wider text-primary hover:underline"
+									>
+										Afficher le code
+									</button>
+								</div>
+							)}
+						</div>
 					</div>
 					<div className="flex flex-col items-center gap-4 w-full border-t pt-6">
 						<p className="text-sm font-medium">