feat(tickets): Rückfrage am Ticket + Antwort durch die Züchterin

Tickets können jetzt eine Rückfrage (Question) tragen und die Züchterin kann
in-app antworten. Feedback um FK-freie Felder Question/Answer/AnsweredAt erweitert
(überlebt Ingest-Wipe); Status-Lebenszyklus Open → NeedsInfo (Rückfrage gestellt)
→ Answered (beantwortet) → Resolved. Migration AddFeedbackQuestionAnswer.

PUT /feedback/{id}: question → NeedsInfo, answer → Answered+AnsweredAt; DTO gibt
die Felder zurück. Tickets-Seite (/hilfe/tickets) zeigt die Rückfrage hervorgehoben
und bietet ein Antwort-Feld + „Antworten"; Status-Badges Offen/Rückfrage offen/
Beantwortet/Gelöst.

Tests: FeedbackEndpointTests (Frage→NeedsInfo, Antwort→Answered, übersteht Ingest),
e2e tickets.spec.ts. dotnet/vitest/playwright grün.

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

GerbilManagerWebAPI/Migrations/20260622174959_AddFeedbackQuestionAnswer.cs

@@ -0,0 +1,49 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace GerbilManagerWebAPI.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddFeedbackQuestionAnswer : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "Answer",
+                table: "Feedback",
+                type: "text",
+                nullable: true);
+
+            migrationBuilder.AddColumn<DateTimeOffset>(
+                name: "AnsweredAt",
+                table: "Feedback",
+                type: "timestamp with time zone",
+                nullable: true);
+
+            migrationBuilder.AddColumn<string>(
+                name: "Question",
+                table: "Feedback",
+                type: "text",
+                nullable: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "Answer",
+                table: "Feedback");
+
+            migrationBuilder.DropColumn(
+                name: "AnsweredAt",
+                table: "Feedback");
+
+            migrationBuilder.DropColumn(
+                name: "Question",
+                table: "Feedback");
+        }
+    }
+}