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.
+
+## Essential Commands
+
+### Development
+- `make tools` - Install all required project dependencies to `tmp/bin`
+- `make test-unit` - Run unit tests for cmd/ and pkg/ directories
+- `make lint` - Run both golang and shell linting
+- `make lint-golang` - Run golangci-lint with auto-fix
+- `make generate` - Generate CRDs, deepcopy, kustomize configs, and docs
+
+### Building
+- `make operator` - Generate manifests and build operator binary (default target)
+- `make build` - Build operator binary to `./tmp/operator`
+- `make operator-image` - Build operator container image
+- Run operator locally (requires prometheus-operator dependencies):
+  1. `./hack/setup-e2e-env.sh` - Setup development environment with Kind cluster
+  2. Build and push operator images:
+     ```bash
+     make operator-image bundle-image operator-push bundle-push \
+         IMAGE_BASE="local-registry:30000/observability-operator" \
+         VERSION=0.0.0-dev \
+         PUSH_OPTIONS=--tls-verify=false
+     ```
+  3. Deploy operator bundle:
+     ```bash
+     ./tmp/bin/operator-sdk run bundle \
+         local-registry:30000/observability-operator-bundle:0.0.0-dev \
+         --install-mode AllNamespaces \
+         --namespace operators --skip-tls
+     ```
+  4. Scale down cluster operator: `kubectl scale --replicas=0 -n operators deployment/observability-operator`
+  5. Run locally: `go run ./cmd/operator/... --zap-devel --zap-log-level=100 --kubeconfig ~/.kube/config 2>&1 | tee tmp/operator.log`
+
+### Testing
+- `make test-e2e` - Run end-to-end tests
+- `./test/run-e2e.sh` - Run E2E tests against local kind cluster
+- `./hack/setup-e2e-env.sh` - Setup local development environment with kind cluster
+
+### Environment Setup
+1. `make tools` - Install project tools
+2. `./hack/setup-e2e-env.sh` - Setup complete development environment
+
+## Architecture Overview
+
+The Observability Operator is a Kubernetes operator that manages monitoring/alerting stacks through CRDs, built on controller-runtime.
+
+### Key Components
+
+**Core APIs** (pkg/apis/):
+- `monitoring.rhobs/v1alpha1` - MonitoringStack CRD for complete monitoring stacks
+- `observability.rhobs/v1alpha1` - Core observability APIs including OpenTelemetry/tracing
+- `uiplugin.rhobs/v1alpha1` - OpenShift console UI plugin integration
+
+**Controllers** (pkg/controllers/):
+- `monitoring/monitoring-stack/` - Manages Prometheus, Alertmanager, and monitoring components
+- `monitoring/thanos-querier/` - Handles Thanos querier deployments
+- `uiplugin/` - Manages OpenShift console plugins and UI components
+- `operator/` - Core operator lifecycle management
+
+**Key Dependencies**:
+- Uses forked prometheus-operator (`github.com/rhobs/obo-prometheus-operator`) for compatibility
+- Integrates with OpenShift APIs for console UI plugins
+- Built on controller-runtime
+
+### Deployment Structure
+
+- `deploy/crds/` - CRD manifests (common + kubernetes-specific)
+- `deploy/dependencies/` - Required dependency resources
+- `deploy/operator/` - Operator deployment manifests
+- `deploy/olm/` - OLM bundle configuration
+
+## Development Notes
+
+- Commonly deployed using OLM (Operator Lifecycle Manager), though manual installation is also supported
+- Generate manifests with `make generate` after modifying Go types in `pkg/apis/`
+- Use conventional commits for automatic changelog/release management
+- The operator can run locally while dependencies (prometheus-operator) run in-cluster
+
+## Testing Specific Files
+
+To run tests for a specific package:
+```bash
+go test ./pkg/controllers/monitoring/monitoring-stack/...
+go test ./pkg/controllers/uiplugin/...
+```