Move SmtpSettings and PageFetcherSettings into their respective models projects

Settings classes now live in the -models project alongside DTOs and client
interfaces, eliminating the Settings/ folder from both API projects.

- SmtpSettings: email-api/Settings/ → email-api-models/Settings/ (namespace EmailApi.Models.Settings)
- PageFetcherSettings: page-fetcher-api/Settings/ → page-fetcher-api-models/Settings/ (namespace PageFetcher.Models.Settings)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Apis/email-api/Services/SmtpEmailDispatcher.cs

@@ -4,6 +4,7 @@ using MailKit.Net.Smtp;
 using MailKit.Security;
 using Microsoft.Extensions.Options;
 using MimeKit;
+using EmailApi.Models.Settings;
 using Models.Settings;
 
 namespace EmailApi.Services;