Add CLAUDE.md documentation

CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+The maestro-addon is a Kubernetes addon that enables Maestro integration with Advanced Cluster Management (ACM). It manages ManifestWorkReplicaSet controllers and provides cloud events-driven communication between hub and managed clusters using either Kafka or gRPC brokers.
+
+## Core Architecture
+
+### Components
+- **Hub Manager** (`pkg/hub/manager.go`): Main orchestrator that manages cluster controllers and message queue authorization
+- **Cluster Controller** (`pkg/hub/controllers/cluster_controller.go`): Handles ManagedCluster lifecycle and Maestro integration
+- **Message Queue Integration** (`pkg/mq/`): Abstraction layer for Kafka and gRPC brokers
+- **Helpers** (`pkg/helpers/`): Utilities for Maestro API and Kafka client operations
+
+### Key Concepts
+- **Broker Types**: Supports two message queue brokers - `kafka` and `grpc` (constants in `pkg/common/constants.go`)
+- **Maestro Service**: External service for cluster management (default: `http://maestro:8000`)
+- **ManifestWorkReplicaSet**: Feature for deploying Kubernetes resources across managed clusters using cloud events
+
+### Entry Point
+Main binary built from `cmd/manager/main.go` creates a CLI with subcommands for hub management.
+
+## Development Commands
+
+### Build
+```bash
+make build          # Build the maestroaddon binary
+make image          # Build container image
+```
+
+### Testing
+```bash
+make test           # Run unit tests (tests files in pkg/)
+make e2e-test       # Run end-to-end tests
+make verify         # Run linting and verification (golangci-lint)
+```
+
+### Deployment
+```bash
+# Install on ACM hub
+helm install maestro-addon ./charts/maestro-addon
+
+# Example configurations
+--set global.imageOverrides.maestroImage=<custom-image>
+--set maestro.broker=kafka
+--set messageQueue.amqStreams.name=<kafka-cluster-name>
+```
+
+## File Structure
+
+- `pkg/hub/`: Hub-side components and controllers
+- `pkg/mq/`: Message queue broker abstractions
+- `pkg/helpers/`: Shared utilities and mocks
+- `charts/maestro-addon/`: Helm chart for deployment
+- `contrib/examples/`: Example CRs and configurations
+- `test/e2e/`: End-to-end test suite
+- `test/performance/`: Performance testing tools
+
+## Key Dependencies
+
+- Open Cluster Management APIs (`open-cluster-management.io/api`)
+- Maestro service integration (`github.com/openshift-online/maestro`)
+- Kafka client (`github.com/confluentinc/confluent-kafka-go/v2`)
+- Kubernetes client libraries
+
+## Configuration
+
+The addon supports configuration via:
+- Command-line flags (maestro-service-address, message-queue-broker-type, etc.)
+- Helm values (`charts/maestro-addon/values.yaml`)
+- Secret-based configs for Kafka and database connections