feat(M0): 工程地基 - Go API + Python 采集骨架 + CI + 数据契约

- api/: Go(chi) 只读 API 骨架, /healthz + 版本化路由(占位), Dockerfile, 单测
- ingestion/: Python 采集/ETL 包骨架, units 单位归一化(纯函数+测试), adapter 协议
- docker-compose.yml: postgres + redis + minio + api
- .github/workflows/ci.yml: Go build/vet/test + Python ruff/pytest
- docs/data-contract.md(两端共享契约) + docs/disclaimer.md(不提供购买声明)
- migrations/ 占位(M1 起填充)

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

ingestion/opengoods/adapters/__init__.py

@@ -0,0 +1,6 @@
+"""Source adapters.
+
+Each open data source (Open Food Facts, USDA FoodData Central, GS1, ...) gets
+its own adapter that fetches raw records and yields them for the ETL layer.
+Adapters must respect each source's robots.txt, rate limits and license.
+"""