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/Application/Dtos/StorageProbe.cs

@@ -0,0 +1,9 @@
+namespace TarninaHub.Application.Dtos;
+
+
+public sealed class StorageProbe
+{
+    public string Label { get; set; } = "probe";
+
+    public DateTimeOffset CreatedAt { get; set; }
+}