Add GitHub Actions workflow for Copilot setup

Introduces a new workflow named "Copilot Setup Steps" that can be triggered manually. The workflow runs on Ubuntu and includes steps for checking out the code and setting up .NET version 9.0.x.

Author: christiannagel

.github/workflows/copilot-setup-steps.yml

@@ -0,0 +1,20 @@
+
+name: Copilot Setup Steps
+
+on:
+  workflow_dispatch
+
+jobs:
+  copilot-setup-steps:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v5
+
+      - name: Setup .NET
+        uses: actions/setup-dotnet@v5
+        with:
+          dotnet-version: '9.0.x'
+