feat(tickets): Rückfragen-Dialog, Verlinkungen, Entwurfssicherung + PWA-Vorbereitung

- Feedback: fixNote (Changelog), agentContext (intern), thread (Q&A-Verlauf);
  3 gefilterte Ansichten (Rückfragen/Offen/Geschlossen)
- Tickets-Text: klickbare Tier-Links (ID→Name), Ticket→Ticket-Links (?focus=),
  Markdown-Links; Antwort-Entwurf pro Ticket in localStorage
- "Fehler melden": Entwurf übersteht App-Wechsel/Schließen (ein gemeinsamer Entwurf)
- entityName als Hyperlink zum referenzierten Datensatz

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

GerbilManagerWebAPI/Migrations/20260622192338_AddFeedbackFixNoteContextThread.cs

@@ -0,0 +1,48 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace GerbilManagerWebAPI.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddFeedbackFixNoteContextThread : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "AgentContext",
+                table: "Feedback",
+                type: "text",
+                nullable: true);
+
+            migrationBuilder.AddColumn<string>(
+                name: "FixNote",
+                table: "Feedback",
+                type: "text",
+                nullable: true);
+
+            migrationBuilder.AddColumn<string>(
+                name: "Thread",
+                table: "Feedback",
+                type: "text",
+                nullable: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "AgentContext",
+                table: "Feedback");
+
+            migrationBuilder.DropColumn(
+                name: "FixNote",
+                table: "Feedback");
+
+            migrationBuilder.DropColumn(
+                name: "Thread",
+                table: "Feedback");
+        }
+    }
+}