Add EmailService with recipient resolution and logging

TDD: IEmailService interface, EmailService resolves member emails + raw addresses (case-insensitive dedup), sends via ISmtpDispatcher, writes a NotificationLog per recipient (sent/failed), and never aborts the batch on a single failure.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

API/ROLAC.API/Services/Notifications/EmailService.cs

@@ -0,0 +1,102 @@
+using Microsoft.EntityFrameworkCore;
+using ROLAC.API.Data;
+using ROLAC.API.Entities.Notifications;
+using ROLAC.API.Services.Logging;
+
+namespace ROLAC.API.Services.Notifications;
+
+/// <summary>
+/// Resolves recipients (member emails + raw addresses, deduped), sends each via the SMTP
+/// dispatcher, and writes a NotificationLog row per recipient. A single failure never aborts the
+/// batch — it is recorded and reported in the summary.
+/// </summary>
+public sealed class EmailService : IEmailService
+{
+    private const int BodyLogMaxLength = 8000;
+
+    private readonly AppDbContext _db;
+    private readonly ISmtpDispatcher _dispatcher;
+    private readonly CurrentUserAccessor _currentUser;
+
+    public EmailService(AppDbContext db, ISmtpDispatcher dispatcher, CurrentUserAccessor currentUser)
+    {
+        _db = db;
+        _dispatcher = dispatcher;
+        _currentUser = currentUser;
+    }
+
+    public async Task<NotificationResult> SendAsync(EmailMessage message, CancellationToken ct = default)
+    {
+        var recipients = await ResolveRecipientsAsync(message, ct);
+        if (recipients.Count == 0) return NotificationResult.Empty;
+
+        var sentBy = message.SentByUserId ?? _currentUser.UserIdOrSystem;
+        var attachments = message.Attachments ?? Array.Empty<EmailAttachment>();
+        var failures = new List<NotificationFailure>();
+        var sentCount = 0;
+
+        foreach (var recipient in recipients)
+        {
+            var log = new NotificationLog
+            {
+                Channel          = NotificationChannels.Email,
+                TargetType       = NotificationTargetTypes.Email,
+                TargetExternalId = recipient.Address,
+                Subject          = message.Subject,
+                MemberId         = recipient.MemberId,
+                Body             = Truncate(message.HtmlBody),
+                SentByUserId     = sentBy,
+                SentAt           = DateTime.UtcNow,
+            };
+
+            try
+            {
+                await _dispatcher.SendAsync(
+                    new OutboundEmail(recipient.Address, message.Subject, message.HtmlBody, attachments), ct);
+                log.Status = NotificationStatuses.Sent;
+                sentCount++;
+            }
+            catch (Exception ex)
+            {
+                log.Status = NotificationStatuses.Failed;
+                log.Error  = ex.Message;
+                failures.Add(new NotificationFailure(recipient.Address, ex.Message));
+            }
+
+            _db.NotificationLogs.Add(log);
+        }
+
+        await _db.SaveChangesAsync(ct);
+        return new NotificationResult(sentCount, failures.Count, failures);
+    }
+
+    private async Task<IReadOnlyList<(string Address, int? MemberId)>> ResolveRecipientsAsync(
+        EmailMessage message, CancellationToken ct)
+    {
+        var resolved = new List<(string Address, int? MemberId)>();
+        var seen = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+
+        if (message.MemberIds.Count > 0)
+        {
+            var members = await _db.Members
+                .Where(member => message.MemberIds.Contains(member.Id) && member.Email != null && member.Email != "")
+                .Select(member => new { member.Id, member.Email })
+                .ToListAsync(ct);
+            foreach (var member in members)
+                if (seen.Add(member.Email!))
+                    resolved.Add((member.Email!, member.Id));
+        }
+
+        foreach (var address in message.Addresses)
+        {
+            var trimmed = address?.Trim();
+            if (!string.IsNullOrWhiteSpace(trimmed) && seen.Add(trimmed))
+                resolved.Add((trimmed, null));
+        }
+
+        return resolved;
+    }
+
+    private static string Truncate(string body) =>
+        body.Length <= BodyLogMaxLength ? body : body[..BodyLogMaxLength] + "…[truncated]";
+}

API/ROLAC.API/Services/Notifications/IEmailService.cs

@@ -0,0 +1,6 @@
+namespace ROLAC.API.Services.Notifications;
+
+public interface IEmailService
+{
+    Task<NotificationResult> SendAsync(EmailMessage message, CancellationToken ct = default);
+}