Add URL parameter auto-submit to login page

[Copilot]

Enables bookmarkable login URLs (e.g., /login/joe@whatever.com) that auto-submit the login request.

Changes

• Login.razor: Added /login/{Email} route
• Login.razor.cs:
  • Added [Parameter] Email property
  • Auto-submit logic in OnParametersSetAsync when email parameter present
  • Validates email format via DataAnnotations.Validator
  • Checks email against AllEmails list when populated (respects allowLoginDropdown config)
  • HasAutoSubmitted flag prevents duplicate submissions on re-render

Example

// URL: /login/joe@whatever.com
protected override async Task OnParametersSetAsync()
{
    // ... fetch AllEmails ...
    
    if (!string.IsNullOrWhiteSpace(Email) && !HasAutoSubmitted)
    {
        HasAutoSubmitted = true;
        Model.Email = Email;
        
        // Validate against AllEmails if populated
        if (AllEmails.Any() && !AllEmails.Contains(Email, StringComparer.OrdinalIgnoreCase))
        {
            await Swal.FireAsync("Error", "Email address not found in allowed users list", ...);
            return;
        }
        
        // Validate format and submit
        if (Validator.TryValidateObject(Model, ...)) { await HandleValidSubmit(); }
    }
}

Normal /login route behavior unchanged.

Original prompt

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This section details on the original issue you should resolve

<issue_title>URL for login user</issue_title>
<issue_description>/login/joe@whatever.com

Automatically submit the login request, so you can bookmark this url for faster login</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes URL for login user #39

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