Add tmate debugging

.github/workflows/ci.yaml

@@ -1,6 +1,12 @@
 name: Unit and integration tests
 on:
   workflow_dispatch:
+    inputs:
+      debug_enabled:
+        type: boolean
+        description: "Run the build with tmate debugging enabled (https://github.com/marketplace/actions/debugging-with-tmate)"
+        required: false
+        default: false
   push:
     branches:
       - main
@@ -27,6 +33,9 @@ jobs:
       - name: Run unit tests
         run: |
           uvx nox -s unit_tests
+      - name: Setup tmate session
+        uses: mxschmitt/action-tmate@v3
+        if: ${{ github.event_name == 'workflow_dispatch' && inputs.debug_enabled }}
       - name: Run system tests
         run: |
           uvx nox -s system_tests