Review global errors to ensure there's a clear recovery path for users

**From incident: [#2025-05-22-multiple-users-blocked](https://docs.google.com/document/d/1keb-FOK1U50c87tB5iSZnXPAq_haxImdbWtM9HLRzE0/edit?tab=t.0)**

## Context

If a person on the Internet — malicious or not — gets 50 bad requests, like a 400 or 500 error, in X minutes, then we temporarily block their IP address for 24 hours. Where this has become an issue is: SSC egresses departmental IP addresses from a single IP, leaving users with a 403 Forbidden error.

Ideally we would know quickly and detect the problem if the app is down.

## To do

- [ ] Create better error messaging when users encounter an error multiple times (ex: 403 Forbidden)

- [ ] Ensure there is a path to support users with 500 errors

- Consider status page like: status.notification.canada.ca
- Consider maintenance page
- Consider path to contact us