Operator: Scaffold Go project with Operator SDK and define Experiment CRD types

[fmallmann]

Parent Issue

Part of #27

Description

Bootstrap the Go operator project using Operator SDK and define the Experiment CRD API types.

Scope

• Initialize Go module with operator-sdk init (domain agentic-layer.ai, group testbench)
• Create the Experiment API type (v1alpha1) with operator-sdk create api
• Define all Go structs:
  • ExperimentSpec: agentRef, dataset, llmAsAJudgeModel, defaultThreshold, scenarios, trigger
  • AgentRef: name, namespace
  • DatasetSource: s3 (bucket, key), url
  • Scenario, Step, Metric, Reference, ToolCall structs
  • TriggerSpec: enabled, event, concurrencyPolicy
• Define ExperimentStatus struct with conditions, generatedResources, lastExecution
• Add kubebuilder validation markers:
  • defaultThreshold and metric threshold validated to 0-1 range
  • dataset and scenarios mutually exclusive (CEL validation rule)
  • Required fields marked appropriately
• Generate CRD manifests with make manifests
• Basic Makefile targets: build, manifests, generate, docker-build

Acceptance Criteria

• operator/ directory with working Go module
• api/v1alpha1/experiment_types.go with all struct definitions
• CRD YAML generated in operator/config/crd/bases/
• OpenAPI validation for threshold ranges and mutual exclusivity
• go build ./... passes
• make manifests generates valid CRD

References

• agent-runtime-operator for project structure reference
• Issue Testbench Operator: Reconcile Experiment CRD to TestWorkflows #27 CRD specification section