ci: probe native macOS Recovery readiness on the existing Ubuntu runner

.gitea/workflows/macos-native-diagnostic.yaml

@@ -0,0 +1,36 @@
+name: Native macOS Recovery diagnostic on Ubuntu
+
+on:
+  workflow_dispatch:
+
+jobs:
+  macos-native-diagnostic:
+    runs-on: ubuntu-latest
+    timeout-minutes: 45
+    env:
+      DOTNET_SKIP_FIRST_TIME_EXPERIENCE: "1"
+      DOTNET_NOLOGO: "1"
+    steps:
+      - name: Checkout diagnostic source
+        uses: actions/checkout@v7
+
+      - name: Setup .NET for the diagnostic helper
+        uses: actions/setup-dotnet@v6
+        with:
+          dotnet-version: "10.0.x"
+
+      - name: Probe native macOS Recovery with existing Docker resources
+        run: dotnet run --file tools/ci/MacOsNativeDiagnostic.cs -- --run --output artifacts/native-macos
+
+      - name: Always clean up only this diagnostic's owned resources
+        if: always()
+        run: dotnet run --file tools/ci/MacOsNativeDiagnostic.cs -- --cleanup --output artifacts/native-macos
+
+      - name: Preserve native diagnostic evidence
+        if: always()
+        uses: actions/upload-artifact@v3
+        with:
+          name: native-macos-recovery-diagnostic
+          path: artifacts/native-macos/
+          if-no-files-found: error
+          retention-days: 7