Show disabled subscriptions in Check Subscription but exclude them from confirmation emails #168

Problem

The admin Check Subscription page lists matching locations without indicating whether they are disabled, and includes all found locations in subscription confirmation emails. This can incorrectly confirm disabled subscriptions as active.

Acceptance criteria

• Keep disabled locations in the admin subscription results and clearly label them as disabled; active locations remain visible.
• Exclude disabled locations from the confirmation email preview and sent email, including HTML, plain text, and optional app links, in both supported languages. Active locations remain included.
• When all matching locations are disabled, do not claim the user has an active subscription or send a misleading active-subscription confirmation; still show the disabled results to the administrator.
• Cover mixed active/disabled locations and the all-disabled case with focused tests.

Context

admin/Pages/CheckSubscription.cshtml displays FoundLocations; CheckSubscription.cshtml.cs passes them to MailTemplates.SubscriptionConfirmation for both preview and sending. The location model exposes the disabled flag, and FindValidLocationsByUserAsync currently returns matching locations regardless of that flag.