feat(M2): Open Food Facts 采集导入 ETL

- adapters/openfoodfacts.py: OFF API 适配器(限速+User-Agent) + JSONL/.gz dump 读取
- etl/transform.py: 纯函数转换(GTIN 校验/净含量解析+归一/营养 per_100g 双能量/过敏原添加剂清洗/关键词分类映射)
- etl/load.py: psycopg upsert(product/food_detail/product_image) + product_source 字段级溯源
- jobs/seed_off.py: CLI(--barcodes API / --dump 文件 / --limit)
- 测试: 13 个离线 transform 单测(fixture) + 可跳过的 DB 集成测试
- 依赖: 增加 psycopg[binary]
- 实跑: 从 OFF API 拉 5 个真实条码入本地 postgres 验证通过
- docs/etl-openfoodfacts.md: 流程/运行/字段映射

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

ingestion/opengoods/jobs/seed_off.py

@@ -0,0 +1,66 @@
+"""Seed the database with Open Food Facts data.
+
+Usage:
+    # from a list of barcodes via the OFF API
+    python -m opengoods.jobs.seed_off --barcodes 3017624010701 5449000000996
+
+    # from a downloaded OFF JSONL dump (optionally .gz), limited to N records
+    python -m opengoods.jobs.seed_off --dump products.jsonl.gz --limit 1000
+
+The OFF read API is rate-limited client-side; for large imports use a dump.
+"""
+
+from __future__ import annotations
+
+import argparse
+import sys
+from collections.abc import Iterator
+
+import psycopg
+
+from opengoods.adapters.openfoodfacts import OpenFoodFactsAdapter, read_dump
+from opengoods.etl.load import default_dsn, ensure_source, load_record
+from opengoods.etl.transform import transform
+
+
+def _raw_records(args: argparse.Namespace) -> Iterator[dict]:
+    if args.dump:
+        records = read_dump(args.dump)
+    else:
+        adapter = OpenFoodFactsAdapter(min_interval=args.min_interval)
+        records = adapter.fetch(args.barcodes)
+    for i, rec in enumerate(records):
+        if args.limit and i >= args.limit:
+            break
+        yield rec
+
+
+def run(args: argparse.Namespace) -> int:
+    loaded = skipped = 0
+    with psycopg.connect(args.dsn, autocommit=False) as conn:
+        source_id = ensure_source(conn)
+        for raw in _raw_records(args):
+            rec = transform(raw)
+            if rec is None:
+                skipped += 1
+                continue
+            load_record(conn, rec, source_id, raw)
+            loaded += 1
+        conn.commit()
+    print(f"loaded={loaded} skipped={skipped}")
+    return 0
+
+
+def main(argv: list[str] | None = None) -> int:
+    parser = argparse.ArgumentParser(description="Seed OpenGoods from Open Food Facts")
+    src = parser.add_mutually_exclusive_group(required=True)
+    src.add_argument("--barcodes", nargs="+", help="barcodes to fetch via the OFF API")
+    src.add_argument("--dump", help="path to an OFF JSONL dump (.jsonl or .jsonl.gz)")
+    parser.add_argument("--limit", type=int, default=0, help="max records to load (0 = all)")
+    parser.add_argument("--min-interval", type=float, default=4.0, help="API throttle seconds")
+    parser.add_argument("--dsn", default=default_dsn(), help="PostgreSQL DSN")
+    return run(parser.parse_args(argv))
+
+
+if __name__ == "__main__":
+    sys.exit(main())