Implement Git-as-K8s control plane with Knative controllers

Build a complete Kubernetes control plane for Git operations using Knative's
pkg framework, go-git for in-memory Git operations, and ko for builds.

Architecture:
- 4 CRDs: GitRepository, GitBranch, GitPushTransaction, GitRepoSync
- Push controller: atomic Git push via go-git with CAS (compare-and-swap)
- Sync controller: two-way sync with in-memory merge base calculation
- Resolver controller: automated 3-way merge for conflicted syncs
- In-cluster Gitea server for backing storage
- Full RBAC, ko-based deployments, and code-gen scaffolding

Note: go.sum needs generation via `go mod tidy` in an environment with
full internet access (knative.dev/pkg v0.0.0-20250520014526-44579e9ce5ed).

https://claude.ai/code/session_01QfFzqKQUsxxBsiZUhuJ3pG

pkg/apis/git/v1alpha1/groupversion_info.go

@@ -0,0 +1,50 @@
+package v1alpha1
+
+import (
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+)
+
+const (
+	// GroupName is the name of the API group.
+	GroupName = "git.k8s.io"
+
+	// Version is the version of the API group.
+	Version = "v1alpha1"
+)
+
+// SchemeGroupVersion is the group version used to register these objects.
+var SchemeGroupVersion = schema.GroupVersion{Group: GroupName, Version: Version}
+
+// Kind takes an unqualified kind and returns a Group-qualified GroupKind.
+func Kind(kind string) schema.GroupKind {
+	return SchemeGroupVersion.WithKind(kind).GroupKind()
+}
+
+// Resource takes an unqualified resource and returns a Group-qualified GroupResource.
+func Resource(resource string) schema.GroupResource {
+	return SchemeGroupVersion.WithResource(resource).GroupResource()
+}
+
+var (
+	// SchemeBuilder adds types to the scheme.
+	SchemeBuilder = runtime.NewSchemeBuilder(addKnownTypes)
+	// AddToScheme applies the SchemeBuilder functions to a scheme.
+	AddToScheme = SchemeBuilder.AddToScheme
+)
+
+func addKnownTypes(scheme *runtime.Scheme) error {
+	scheme.AddKnownTypes(SchemeGroupVersion,
+		&GitRepository{},
+		&GitRepositoryList{},
+		&GitBranch{},
+		&GitBranchList{},
+		&GitPushTransaction{},
+		&GitPushTransactionList{},
+		&GitRepoSync{},
+		&GitRepoSyncList{},
+	)
+	metav1.AddToGroupVersion(scheme, SchemeGroupVersion)
+	return nil
+}