fix: sync child resources by owner UID

[CandidXD]

What changed

• replace TypeMeta-dependent ownerRef matching with immutable UID matching
• recognize resources owned by either the underlying custom resource or Middleware
• preserve label fallback for resources owned through other intermediate objects
• reject stale same-identity owner references with a different UID
• cover Deployment -> ReplicaSet -> Pod discovery when informer objects have empty TypeMeta

Why

client-go LIST objects may omit per-item kind and apiVersion. The synchronizer compared those empty fields with owner references, so a running exporter Pod could be omitted from Middleware.status.customResources.include.pods even though its Deployment and Service were present.

Impact

The status schema, sorting, CRDs, baselines, and label compatibility path are unchanged. Correct UID ownership now works even without TypeMeta; stale same-name resources with a different UID are no longer treated as current children.

Validation

• go test ./internal/service/synchronizer -run "TestHasOwnerUID|TestOwnerReferencesMatch|TestCollectOwnedPods|TestPVCBelongsToStatefulSet" -count=1
• go test ./internal/service/synchronizer ./internal/service/watcher -race -count=1
• go test ./... -count=1
• go vet ./...
• git diff --check
• independent code review: 0 critical, 0 important

Remaining gate

Runtime verification in the 52 environment will be performed separately by the maintainer.