# TASK 1: Add Framework-Owned Export Contracts, Shared Redshift `UNLOAD` Executor, And Curated S3 Path Usage

## Summary

Add framework-owned export contracts and shared execution seam for exporting curated data from tenant Redshift to S3 with `UNLOAD`.

## Dependencies

- [TASK 0](./TASK0.md) - Freeze minimal `curated_to_s3` delivery contract

## Files to Create

### 1. Shared export execution types

Create shared types equivalent to:

- `CuratedExportRequest`
- `CuratedExportTargetDefinition`
- `ICuratedExportCatalog`
- `ICuratedExportExecutor`
- `CuratedExportExecutor`

Minimum logical fields:

- tenant warehouse descriptor,
- target name,
- export `SELECT` SQL,
- logical entity name,
- output S3 prefix or object key seed,
- batch and tenant context needed for path generation.

## Files to Modify

### 2. Warehouse/export module wiring

Register new shared export executor in DI near current shared ETL and warehouse execution services.

### 3. Existing S3 path helper usage

Reuse existing curated path/key builder logic instead of adding ad-hoc string formatting in stage code.

## Progress Checklist

- [ ] Shared export contract types created
- [ ] Shared export executor created
- [ ] DI wiring added
- [ ] Tenant warehouse connection reuse implemented
- [ ] Central `UNLOAD` command generation implemented
- [ ] Existing curated S3 path helper reused
- [ ] Executor diagnostics shape defined
- [ ] Unit tests added for command generation and failure path

## Required Behavior

- executor opens tenant warehouse connection through existing tenant warehouse connection factory,
- executor builds safe `UNLOAD` command for Parquet output,
- executor writes to standard curated S3 layout,
- executor keeps command generation centralized,
- shared contract can describe export targets for any adapter,
- executor surfaces per-target diagnostics useful for stage failure packaging,
- executor does not own adapter target list.

## Testing

### Unit tests

Add unit tests for:

- `UNLOAD` command generation,
- S3 path generation usage,
- per-target execution diagnostics,
- failure propagation on Redshift command error.

## Acceptance Criteria

- shared export executor exists,
- shared export catalog contract exists,
- executor uses tenant-resolved Redshift connection,
- executor generates Parquet `UNLOAD` commands centrally,
- executor writes to standard curated S3 path shape,
- unit tests cover success and failure command paths.

## Notes

- Keep contracts and executor generic enough for later sources.
- Do not add Athena or Glue behavior here.