Major milestone: Complete apt-ostree bootc compatibility and OCI integration

- ✅ Real package installation (replaced mock installation)
- ✅ Real OSTree commit creation from installed packages
- ✅ OCI image creation from both commits and rootfs
- ✅ Full bootc compatibility with proper labels
- ✅ Comprehensive test suite (test-bootc-apt-ostree.sh)
- ✅ Container tool validation (skopeo, podman)
- ✅ Updated compatibility reports for Ubuntu Questing
- ✅ Fixed OCI schema version and field naming issues
- ✅ Temporary directory lifecycle fixes
- ✅ Serde rename attributes for OCI JSON compliance

Ready for Aurora-style workflow deployment!

test-bootc-image/index.json

@@ -0,0 +1,17 @@
+{
+  "manifests": [
+    {
+      "annotations": {
+        "org.opencontainers.image.ref.name": "latest"
+      },
+      "digest": "sha256:0987de77977350be20f2796160ac3626b92f3f1b2fc16b42d4f64445575b66d2",
+      "mediaType": "application/vnd.oci.image.manifest.v1+json",
+      "platform": {
+        "architecture": "amd64",
+        "os": "linux"
+      },
+      "size": 506
+    }
+  ],
+  "schemaVersion": 2
+}