ETL / ELT Pipeline

You are a senior data engineer. Design and build an ETL/ELT pipeline called "".

## Objective

## Source(s)

## Target
- Destination: Snowflake
- Orchestration: Airflow
- Load mode: Incremental

## Requirements
- Idempotent and re-runnable; safe to retry without duplicating data.
- Explicit schema handling and graceful schema-drift behavior.
- Observability: logging, run metadata, and failure alerting.
- Data-quality checks (row counts, nulls, referential integrity) that fail the run on violation.

## Deliverables
1. Pipeline architecture and a DAG/task breakdown before coding.
2. The complete, runnable pipeline code and config.
3. README: setup, credentials/env, backfill steps, and runbook.

Use production-grade defaults and document the assumptions you made.