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/reconciler/push/controller.go

@@ -0,0 +1,71 @@
+package push
+
+import (
+	"context"
+	"time"
+
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/client-go/dynamic"
+	"k8s.io/client-go/dynamic/dynamicinformer"
+	"k8s.io/client-go/tools/cache"
+	"knative.dev/pkg/configmap"
+	"knative.dev/pkg/controller"
+	"knative.dev/pkg/injection"
+	"knative.dev/pkg/logging"
+
+	gitv1alpha1 "github.com/imjasonh/git-k8s/pkg/apis/git/v1alpha1"
+	gitclient "github.com/imjasonh/git-k8s/pkg/client"
+)
+
+var pushTransactionGVR = schema.GroupVersionResource{
+	Group:    gitv1alpha1.GroupName,
+	Version:  gitv1alpha1.Version,
+	Resource: "gitpushtransactions",
+}
+
+// NewController creates a new controller for GitPushTransaction resources.
+func NewController(ctx context.Context, cmw configmap.Watcher) *controller.Impl {
+	logger := logging.FromContext(ctx)
+
+	// Get dynamic client from the injected config.
+	cfg := injection.GetConfig(ctx)
+	dynClient, err := dynamic.NewForConfig(cfg)
+	if err != nil {
+		logger.Fatalf("Error building dynamic client: %v", err)
+	}
+
+	gitClient := gitclient.NewFromDynamic(dynClient)
+	ctx = gitclient.WithClient(ctx, gitClient)
+
+	// Create dynamic informer for GitPushTransaction.
+	factory := dynamicinformer.NewDynamicSharedInformerFactory(dynClient, 30*time.Second)
+	transactionInformer := factory.ForResource(pushTransactionGVR)
+
+	r := &Reconciler{
+		dynamicClient: dynClient,
+		gitClient:     gitClient,
+	}
+
+	impl := controller.NewContext(ctx, r, controller.ControllerOptions{
+		WorkQueueName: "GitPushTransactions",
+		Logger:        logger,
+	})
+
+	logger.Info("Setting up event handlers for GitPushTransaction")
+
+	transactionInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
+		AddFunc: func(obj interface{}) {
+			impl.Enqueue(obj)
+		},
+		UpdateFunc: func(oldObj, newObj interface{}) {
+			impl.Enqueue(newObj)
+		},
+	})
+
+	// Start the informer factory.
+	factory.Start(ctx.Done())
+	factory.WaitForCacheSync(ctx.Done())
+
+	return impl
+}
+