feat: Add Helm chart for Kubernetes deployment

Feature Request

Summary

Add an official Helm chart to enable easy deployment of Repowise on Kubernetes clusters.

Motivation

Repowise currently supports Docker and docker-compose deployment, but many teams run production workloads on Kubernetes. A Helm chart would:

• Enable one-command deployment to any k8s cluster (helm install repowise ./charts/repowise)
• Provide configurable values for API keys, resource limits, persistence, and ingress
• Make it easy to manage upgrades and rollbacks
• Allow integration with existing k8s tooling (ArgoCD, Flux, etc.)

Proposed Implementation

• Add a charts/repowise/ directory with a standard Helm chart structure
• Include templates for: Deployment, Service, PVC (for SQLite + indexed data at /data), Ingress, Secret, ServiceAccount
• Configurable values for:
  • LLM provider API keys (Anthropic, OpenAI, Gemini)
  • Embedder selection (mock, openai, etc.)
  • Resource requests/limits
  • Persistence (storage class, size)
  • Ingress (host, TLS, annotations)
  • Backend/frontend ports
• Probes pointing at the API health endpoint
• Documentation in charts/repowise/README.md

Context

The existing docker/Dockerfile and docker-compose.yml provide the container foundation. The Helm chart would build on top of the same image, mapping the same env vars and volume mounts into k8s-native resources.

Start by reviewing docker/Dockerfile and docker-compose.yml to identify the image, environment variables, ports, volume mounts, and API health endpoint. Add the standard resources under charts/repowise/, including configurable values for providers, persistence, resources, ingress, ports, probes, and the listed Kubernetes objects. Done means the chart supports the described deployment configuration and charts/repowise/README.md documents its use.