fix(products): bomb-safe image processing + per-image error isolation; honest claim/resumability docs (SLICE-7 review)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

backend/tests/test_products_imagefetch.py

@@ -121,6 +121,28 @@ def test_run_phase_classifies_each_image(pool, host, tmp_path):
     assert _run_status(pool, rid) == "complete_with_problems"
 
 
+def test_unexpected_processing_error_marks_image_failed_not_wedged(pool, host, tmp_path, monkeypatch):
+    # If anything after the fetch raises unexpectedly (e.g. objectstore.put),
+    # the image is marked failed and the run still reaches a terminal status —
+    # never stranded in fetching_images.
+    store = objectstore.LocalObjectStore(str(tmp_path))
+    sf, _acct, rid = _seed(pool)
+    p = _product(pool, sf, "lamp")
+    iid = _image(pool, p, f"{host}/good.png", rid, position=1)
+
+    def _boom(*a, **k):
+        raise RuntimeError("storage down")
+    monkeypatch.setattr(store, "put", _boom)
+
+    imagefetch.run_image_phase(pool, store, rid, allow_private=True)
+    with pool.connection() as conn:
+        counts = repo.run_image_counts(conn, rid)
+    assert counts["failed"] == 1 and counts["pending"] == 0
+    assert _run_status(pool, rid) == "complete_with_problems"
+    row = _img_row(pool, iid)
+    assert row["status"] == "failed"
+
+
 def test_resume_after_kill_completes_remaining(pool, host, tmp_path):
     store = objectstore.LocalObjectStore(str(tmp_path))
     sf, _acct, rid = _seed(pool)