Removes Copilot AI coding agent instructions

Removes the Copilot AI coding agent instructions and related files.
Adds an agents guide to provide guidelines for AI agents, coding standards, and resilience.
Adds a workflow for copilot setup steps.

Author: niemyjski

.github/copilot-instructions.md

@@ -0,0 +1,29 @@
+name: "Copilot Setup"
+
+on:
+  workflow_dispatch:
+  push:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+  pull_request:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+
+jobs:
+  copilot-setup-steps:
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: read
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v6
+
+      - name: Setup .NET Core
+        uses: actions/setup-dotnet@v5
+        with:
+          dotnet-version: |
+            8.0.x
+            9.0.x
+            10.0.x