feat: add authentication system (login, users, auth middleware)

- server/auth.js: JWT middleware and auth routes
- src/stores/auth.js + useAuthFetch.js: client-side auth state
- src/views/LoginView.vue + UsersView.vue: login and user management UI
- router, sidebar, App.vue: guard routes behind auth
- COOLIFY.md: add real deployment IDs

server/auth.js

@@ -0,0 +1,22 @@
+import jwt from "jsonwebtoken";
+
+const JWT_SECRET =
+  process.env.JWT_SECRET || "sbsports-dev-secret-change-in-prod";
+const JWT_EXPIRES = "8h";
+
+export function signToken(payload) {
+  return jwt.sign(payload, JWT_SECRET, { expiresIn: JWT_EXPIRES });
+}
+
+export function requireAuth(req, res, next) {
+  const header = req.headers.authorization || "";
+  const token = header.startsWith("Bearer ") ? header.slice(7) : null;
+  if (!token) return res.status(401).json({ error: "No autenticado" });
+
+  try {
+    req.user = jwt.verify(token, JWT_SECRET);
+    next();
+  } catch {
+    res.status(401).json({ error: "Token inválido o expirado" });
+  }
+}