Introduce componentized generic workflow orchestration for gridded data to DHIS2 DataValueSet [CLIM-523]

[abyot]

Summary

This PR introduces a componentized, generic FastAPI workflow pipeline to fetch gridded datasets and generate DHIS2-compatible dataValueSet output through a single workflow endpoint.

The workflow is built from reusable components:

1. feature_source
2. download_dataset
3. temporal_aggregation
4. spatial_aggregation
5. build_datavalueset

Each component is also discoverable and executable via dedicated component endpoints.

What’s Included

1) Generic workflow orchestration

• Added single end-to-end workflow endpoint:
  • POST /workflows/dhis2-datavalue-set
• Added workflow discovery endpoint:
  • GET /workflows
• Added workflow definition support via YAML (data/workflows/*.yaml) with workflow_id selection.

2) Componentization

• Added reusable component layer and catalog:
  • GET /components
• Added dedicated component execution endpoints:
  • POST /components/feature-source
  • POST /components/download-dataset
  • POST /components/temporal-aggregation
  • POST /components/spatial-aggregation
  • POST /components/build-datavalue-set
• Reused existing data_xxx services under component wrappers (no data-layer duplication).

3) Request normalization and generic mapping

• Kept a simple flat public request payload.
• Normalized to internal execution model for component orchestration.
• Supports dataset-aware date normalization and org-unit feature sourcing.

4) Runtime and observability

• Added per-component runtime tracking:
  • start/end timestamp
  • duration
  • status
  • summarized inputs/outputs
• Added run IDs and persisted run logs under downloads workflow run directory.
• Added response controls for component run details:
  • include_component_run_details
  • component_run_details_included
  • component_run_details_available

5) Robust validation and error contracts

• Added step-level workflow validation (component, version, config).
• Added stable error metadata in failure responses/logs:
  • error_code
  • failed_component
  • failed_component_version
  • run_id
• Maintained explicit error classes:
  • 422 validation/config issues
  • 503 upstream connectivity issues
  • 500 execution failures