feat: Add Kubernetes deployment support

[MoonBoi9001]

Summary

This PR adds Kubernetes deployment manifests and documentation, enabling the Service Quality Oracle to be deployed on Kubernetes clusters while leveraging the existing state persistence features.

What This PR Adds

New Kubernetes Manifests (k8s/ directory)

• deployment.yaml: Production-ready pod specification with health checks and resource limits
• persistent-volume-claim.yaml: Storage volumes for /app/data and /app/logs
• configmap.yaml: Non-sensitive configuration management
• secrets.yaml.example: Template for sensitive credentials
• README.md: Comprehensive deployment guide

Enhanced .gitignore

• Added k8s/secrets.yaml to prevent committing actual secrets
• Added common Kubernetes patterns (kubeconfig, Helm, Kustomize, temp files)

Key Design Decisions

1. Zero application code changes - Kubernetes volumes mount at the same paths as docker-compose
2. Leverages existing features - Circuit breaker, BigQuery cache, and state tracking work unchanged
3. ConfigMap + Secrets separation - Follows K8s best practices for configuration
4. Multi-cloud support - Configurable storage classes for AWS, GKE, Azure

How It Works

The existing application already stores state in /app/data:

• Circuit breaker log (implemented in PR feat(SQO): Introduce circuit breaker. #9)
• Last run tracking
• BigQuery cache (implemented in PR feat: Add BigQuery caching with 30-minute freshness #12)
• CSV outputs

This PR simply ensures these directories persist across Kubernetes pod restarts using PersistentVolumeClaims.

Testing

# Deploy to Kubernetes
kubectl apply -f k8s/

# Verify persistent volumes
kubectl get pvc -l app=service-quality-oracle

# Check pod health
kubectl describe pod -l app=service-quality-oracle

Next Steps

After merging, trigger the CD pipeline (from PR #13) with a Minor version bump to create v0.2.0.

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Note: This PR builds upon the excellent work from previous PRs - it simply makes the service deployable on Kubernetes infrastructure.