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-rootfs-image/blobs/sha256/57e090b16d8c8dc4d5f6354bfdb82cf3b1d990df90a0b087153d5e346aac1aae

@@ -0,0 +1,18 @@
+{
+  "annotations": {
+    "org.aptostree.created": "2025-07-20T20:23:57.611718907+00:00"
+  },
+  "config": {
+    "digest": "sha256:57eddc5980880f08aaf697f800360ed7d06fcb31ebf44333cdf7185a2a7705ec",
+    "mediaType": "application/vnd.oci.image.config.v1+json",
+    "size": 911
+  },
+  "layers": [
+    {
+      "digest": "sha256:55f5b5c89ee9c11df8855a5bba469bc08793836e4e56479c435b3eeb89001a2b",
+      "mediaType": "application/vnd.oci.image.layer.v1.tar+gzip",
+      "size": 214
+    }
+  ],
+  "schemaVersion": 2
+}