PHILADELPHIA — Maybe you don’t want to hear this right now. Maybe you need to hear this right now. But in the wake of the 49ers’ gut-punch NFC Championship Game loss, it’s important to note that the Niners’ championship window remains wide open for the 2023 season and likely beyond. Even if Brock Purdy’s elbow injury leaves him sidelined for the start — or all — of the 2023 campaign, the Niners are built to win games. While other teams in the league are quarterback-dependent to win, the Niners proved this year they can win with merely competent play at the position — such is the strength of th…