This pull request introduces a major storage refactoring and breaking changes to the OpenRAG Helm chart, consolidating several PersistentVolumeClaims (PVCs) and updating the configuration and deployment logic accordingly. It also adds a migration job to help users upgrade safely and updates the Helm chart version to 0.2.0. If you are upgrading from a previous version, please follow the migration instructions to avoid data loss.

Major storage refactor and migration:

• Consolidated legacy PVCs (config, keys, documents) into new data and shared PVCs, simplifying volume management for the backend and Langflow components. Old PVCs are deprecated and should be deleted after migration. (kubernetes/helm/openrag/templates/backend/deployment.yaml [1] [2]; kubernetes/helm/openrag/templates/langflow/deployment.yaml [3] [4]; kubernetes/helm/openrag/templates/storage/backend-sc.yaml [5] [6]; kubernetes/helm/openrag/templates/storage/config-pvc.yaml [7]; kubernetes/helm/openrag/templates/storage/keys-pvc.yaml [8]; kubernetes/helm/openrag/templates/storage/data-pvc.yaml [9]
• Added a migration job (storage-migration) to copy existing config and keys to the new data volume during upgrade. This job must be enabled in values.yaml when upgrading from older versions. (kubernetes/helm/openrag/templates/storage/migration-job.yaml [1]; kubernetes/helm/openrag/templates/NOTES.txt [2]

Deployment and configuration updates:

• Updated backend and Langflow deployments to mount the new data and shared volumes, and removed legacy volume mounts and related init containers. (kubernetes/helm/openrag/templates/backend/deployment.yaml [1] [2]; kubernetes/helm/openrag/templates/langflow/deployment.yaml [3] [4]
• Centralized path configuration using new environment variables and values in values.yaml, supporting custom directory layouts. (kubernetes/helm/openrag/templates/backend/backend-dotenv.yaml [1]; .env.example [2]; docker-compose.yml [3]

Default data loading and flows:

• Improved logic for loading default documents and flows, now using the shared volume and supporting robust download with retry mechanisms for flows. (kubernetes/helm/openrag/templates/backend/deployment.yaml kubernetes/helm/openrag/templates/backend/deployment.yamlL105-R177)
• Changed the flag for disabling default document loading: backend.persistence.documents.enabled is removed; use backend.persistence.documents.loadDefaults: false instead. (kubernetes/helm/openrag/templates/NOTES.txt kubernetes/helm/openrag/templates/NOTES.txtR80-R97)

Versioning and documentation:

• Bumped Helm chart version to 0.2.0 and documented the breaking changes and migration steps in the release notes. (kubernetes/helm/openrag/Chart.yaml [1]; kubernetes/helm/openrag/templates/NOTES.txt [2]

Please review the release notes and migration instructions carefully before upgrading.