feat: orchestrator step_scrape with retry + stale-data fallback

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

backend/tests/test_orchestrator.py

@@ -168,3 +168,40 @@ def test_send_admin_alert_calls_backend(monkeypatch):
     assert len(sent) == 1
     assert "[MealPlanner ALERT] boom" in sent[0]["subject"]
     assert sent[0]["to"] == "admin@example.com"
+
+
+# ---------------------------------------------------------------------------
+# step_scrape tests
+# ---------------------------------------------------------------------------
+
+def test_step_scrape_idempotent(db, weekly_run_scraped):
+    original_ts = weekly_run_scraped.scraped_at
+    from app.services.orchestrator.steps import step_scrape
+    step_scrape(weekly_run_scraped, db)
+    assert weekly_run_scraped.scraped_at == original_ts
+
+
+def test_step_scrape_success(db, weekly_run, monkeypatch):
+    monkeypatch.setattr(
+        "app.services.orchestrator.steps.ScraperService.run_scrape",
+        lambda self, **kw: {"status": "success", "items_scraped": 42},
+    )
+    from app.services.orchestrator.steps import step_scrape
+    step_scrape(weekly_run, db)
+    assert weekly_run.scraped_at is not None
+    assert weekly_run.used_stale_data is False
+
+
+def test_step_scrape_both_fail_marks_stale(db, weekly_run, monkeypatch):
+    monkeypatch.setattr(
+        "app.services.orchestrator.steps.ScraperService.run_scrape",
+        lambda self, **kw: {"status": "failed", "error": "timeout"},
+    )
+    monkeypatch.setattr(
+        "app.services.orchestrator.steps.send_admin_alert",
+        lambda subject, body: None,
+    )
+    from app.services.orchestrator.steps import step_scrape
+    step_scrape(weekly_run, db)
+    assert weekly_run.used_stale_data is True
+    assert weekly_run.scraped_at is not None