feat(backend): add communication, tester, admin and middleman modules

Implement step 17 modules: threads/messages, notifications with automation (submission.created, idea.created, grant_call.opened), innovation test feedback, admin panel (submissions, verify, metrics, grant call status), Middleman adaptation and partnerships. Split multi-type files into one type per file and replace object-valued dictionaries with string-valued maps in data contracts (migrations 0006/0007).

backend/Infrastructure/Persistence/MessageRow.cs

@@ -0,0 +1,17 @@
+using Dahomey.Cbor.Attributes;
+
+namespace TarninaHub.Infrastructure.Persistence;
+
+
+internal sealed class MessageRow
+{
+    [CborProperty("id")] public string Id { get; set; } = string.Empty;
+
+    [CborProperty("thread")] public string Thread { get; set; } = string.Empty;
+
+    [CborProperty("author")] public string Author { get; set; } = string.Empty;
+
+    [CborProperty("body")] public string Body { get; set; } = string.Empty;
+
+    [CborProperty("created_at")] public DateTimeOffset CreatedAt { get; set; }
+}