feat(ingestion): harden OFF ingestion for bulk seeding

- Add retry/backoff (429 + 5xx, Retry-After aware) to the OFF adapter so
  transient API errors no longer abort a run.
- Clamp bounded text fields (serving_size, net_content_unit,
  country_of_origin) to their column widths in transform; long OFF values
  previously raised StringDataRightTruncation and rolled back the batch.
- Load each record inside a savepoint (load_record_safe) so one malformed
  source record is skipped instead of aborting the whole import; jobs now
  report an errored count.
- Tests for retry behaviour, serving_size clamping, and per-record isolation.

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

ingestion/opengoods/etl/transform.py

@@ -78,6 +78,14 @@ def map_category(raw: dict) -> str | None:
     return None
 
 
+def _clamp(value: str | None, max_len: int) -> str | None:
+    """Trim a string to fit a bounded DB column; external data length varies."""
+    if value is None:
+        return None
+    value = value.strip()
+    return value[:max_len] or None
+
+
 def _clean_tags(tags: list[str] | None, prefix: str = "") -> list[str]:
     out: list[str] = []
     for t in tags or []:
@@ -143,16 +151,16 @@ def transform(raw: dict) -> dict | None:
         "brand": brand,
         "category_path": map_category(raw),
         "net_content_value": net_value,
-        "net_content_unit": net_unit,
+        "net_content_unit": _clamp(net_unit, 16),
         "net_content_canonical": net_canonical,
-        "country_of_origin": (raw.get("countries") or "").split(",")[0].strip() or None,
+        "country_of_origin": _clamp((raw.get("countries") or "").split(",")[0].strip() or None, 64),
         "food": {
             "ingredients_text": raw.get("ingredients_text") or None,
             "allergens": _clean_tags(raw.get("allergens_tags")),
             "additives": _clean_tags(raw.get("additives_tags")),
             "nutriments": transform_nutriments(raw.get("nutriments") or {}),
             "nutrition_basis": "per_100g",
-            "serving_size": raw.get("serving_size") or None,
+            "serving_size": _clamp(raw.get("serving_size") or None, 32),
             "nutri_score": (raw.get("nutriscore_grade") or "").upper()[:1] or None,
         },
         "image_url": raw.get("image_front_url") or raw.get("image_url") or None,