Add unit tests and GitRepoSync e2e test

Add unit tests for all packages that previously had zero test coverage:
- pkg/apis/git/v1alpha1: defaults, deepcopy, scheme registration, constants
- pkg/client: toUnstructured/fromUnstructured round-trips, context injection
- pkg/reconciler/push: splitKey, nestedFieldNoCopy, unstructuredNestedStringMap, base64 decoding
- pkg/reconciler/sync: splitKey
- pkg/reconciler/resolver: splitKey, changeName

Add e2e test exercising the sync controller:
- Creates second Gitea repo and GitRepository CR
- Creates GitBranch CRs with headCommit set via status subresource patch
- Creates GitRepoSync CR and verifies the sync controller processes it

https://claude.ai/code/session_01QfFzqKQUsxxBsiZUhuJ3pG

.github/workflows/ci.yaml

@@ -306,10 +306,134 @@ jobs:
           echo ""
           echo "Branch feature-test verified on git server!"
 
+      # --- GitRepoSync e2e test ---
+      # Create a second repo on Gitea to test sync between two repos.
+      - name: Create second test repository on Gitea
+        run: |
+          kubectl exec -n git-system deploy/gitea -- \
+            curl -sf -X POST http://localhost:3000/api/v1/user/repos \
+            -H 'Content-Type: application/json' \
+            -u testadmin:testpassword123 \
+            -d '{"name":"test-repo-b","auto_init":true,"default_branch":"main"}'
+          echo ""
+          echo "Second test repository created"
+
+      - name: Create second GitRepository CR
+        run: |
+          cat <<'EOF' | kubectl apply -f -
+          apiVersion: git-k8s.imjasonh.com/v1alpha1
+          kind: GitRepository
+          metadata:
+            name: test-repo-b
+            namespace: default
+          spec:
+            url: http://gitea.git-system.svc.cluster.local:3000/testadmin/test-repo-b.git
+            defaultBranch: main
+            auth:
+              secretRef:
+                name: gitea-creds
+          EOF
+
+      - name: Create GitBranch CRs for sync test
+        run: |
+          # Get the head commit from each repo via Gitea API
+          COMMIT_A=$(kubectl exec -n git-system deploy/gitea -- \
+            curl -sf http://localhost:3000/api/v1/repos/testadmin/test-repo/branches/main \
+            -u testadmin:testpassword123 | python3 -c "import sys,json; print(json.load(sys.stdin)['commit']['id'])")
+          echo "Repo A main commit: $COMMIT_A"
+
+          COMMIT_B=$(kubectl exec -n git-system deploy/gitea -- \
+            curl -sf http://localhost:3000/api/v1/repos/testadmin/test-repo-b/branches/main \
+            -u testadmin:testpassword123 | python3 -c "import sys,json; print(json.load(sys.stdin)['commit']['id'])")
+          echo "Repo B main commit: $COMMIT_B"
+
+          # Create GitBranch CRs
+          cat <<'EOF' | kubectl apply -f -
+          apiVersion: git-k8s.imjasonh.com/v1alpha1
+          kind: GitBranch
+          metadata:
+            name: test-repo-main
+            namespace: default
+          spec:
+            repositoryRef: test-repo
+            branchName: main
+          EOF
+
+          cat <<'EOF' | kubectl apply -f -
+          apiVersion: git-k8s.imjasonh.com/v1alpha1
+          kind: GitBranch
+          metadata:
+            name: test-repo-b-main
+            namespace: default
+          spec:
+            repositoryRef: test-repo-b
+            branchName: main
+          EOF
+
+          # Set headCommit via status subresource patch
+          kubectl patch gitbranch test-repo-main -n default \
+            --type=merge --subresource=status \
+            -p "{\"status\":{\"headCommit\":\"${COMMIT_A}\"}}"
+
+          kubectl patch gitbranch test-repo-b-main -n default \
+            --type=merge --subresource=status \
+            -p "{\"status\":{\"headCommit\":\"${COMMIT_B}\"}}"
+
+          kubectl get gitbranches -A -o wide
+
+      - name: Create GitRepoSync
+        run: |
+          cat <<'EOF' | kubectl apply -f -
+          apiVersion: git-k8s.imjasonh.com/v1alpha1
+          kind: GitRepoSync
+          metadata:
+            name: test-sync
+            namespace: default
+          spec:
+            repoA:
+              name: test-repo
+            repoB:
+              name: test-repo-b
+            branchName: main
+          EOF
+          kubectl get gitreposyncs -A
+
+      - name: Wait for sync controller to process
+        run: |
+          echo "Waiting for GitRepoSync to be processed..."
+          for i in $(seq 1 30); do
+            PHASE=$(kubectl get gitreposync test-sync -n default \
+              -o jsonpath='{.status.phase}' 2>/dev/null)
+            MSG=$(kubectl get gitreposync test-sync -n default \
+              -o jsonpath='{.status.message}' 2>/dev/null)
+            echo "  attempt ${i}: phase=${PHASE:-empty} message=${MSG:-empty}"
+            if [ -n "$PHASE" ]; then
+              echo "Sync controller has set phase: $PHASE"
+              break
+            fi
+            sleep 2
+          done
+
+      - name: Verify GitRepoSync status
+        run: |
+          echo "=== GitRepoSync status ==="
+          kubectl get gitreposync test-sync -n default -o yaml
+
+          PHASE=$(kubectl get gitreposync test-sync -n default \
+            -o jsonpath='{.status.phase}')
+          echo "Phase: $PHASE"
+          # The sync controller should have processed this - phase should be set
+          if [ -z "$PHASE" ]; then
+            echo "FAIL: sync controller did not set a phase"
+            kubectl logs -n git-system deploy/sync-controller --tail=100
+            exit 1
+          fi
+          echo "GitRepoSync e2e test passed! Phase: $PHASE"
+
       - name: Collect diagnostics
         if: ${{ failure() }}
         uses: chainguard-dev/actions/kind-diag@main
         with:
           artifact-name: kind-logs
           cluster-resources: nodes,namespaces,crds
-          namespace-resources: pods,deployments,services,gitrepositories,gitbranches,gitpushtransactions
+          namespace-resources: pods,deployments,services,gitrepositories,gitbranches,gitpushtransactions,gitreposyncs