feat: add user accounts, authentication, and game history with Prisma 7

- Implement user registration and login with NextAuth v5 (email/password, JWT)
- Add authentication modal in UI with login/register tabs
- Create user profile screen showing game statistics and history
- Integrate Prisma 7 ORM with SQLite database for data persistence
- Store game results (mode, path, clicks, time) in database
- Auto-save completed games only when user is authenticated
- Separate business logic into reusable hooks (useSoloGame, useMultiGame)
- Organize UI into composable screen components (HomeScreen, SoloScreen, ProfileScreen, etc)
- Add session persistence across F5 refresh for solo and multiplayer
- Style auth modal, account button, and profile stats dashboard

auth.ts

@@ -0,0 +1,39 @@
+import NextAuth from "next-auth";
+import Credentials from "next-auth/providers/credentials";
+import bcrypt from "bcryptjs";
+import { prisma } from "./lib/prisma";
+
+export const { handlers, auth, signIn, signOut } = NextAuth({
+  providers: [
+    Credentials({
+      credentials: {
+        email: { label: "Email", type: "email" },
+        password: { label: "Mot de passe", type: "password" },
+      },
+      async authorize(credentials) {
+        if (!credentials?.email || !credentials?.password) return null;
+        const user = await prisma.user.findUnique({
+          where: { email: credentials.email as string },
+        });
+        if (!user) return null;
+        const valid = await bcrypt.compare(credentials.password as string, user.password);
+        if (!valid) return null;
+        return { id: user.id, name: user.name, email: user.email };
+      },
+    }),
+  ],
+  session: { strategy: "jwt" },
+  pages: {
+    signIn: "/",
+  },
+  callbacks: {
+    jwt({ token, user }) {
+      if (user) token.id = user.id;
+      return token;
+    },
+    session({ session, token }) {
+      if (session.user) session.user.id = token.id as string;
+      return session;
+    },
+  },
+});