fix: source sade sati from domain service

scripts/jyotish_api_server.py

@@ -4424,6 +4424,13 @@ class JyotishAPIHandler(BaseHTTPRequestHandler):
                 moon_lon=moon_lon,
                 current_date=datetime.utcnow(),
             )
+            sade_sati = calculation_service.compute_sade_sati(
+                moon_degree=canonical_chart['planets']['Moon']['lon'],
+                asc_degree=canonical_chart['ascendant']['lon'],
+                reference_date=body.get('transit_date') or body.get('today') or body.get('current_date') or datetime.utcnow().strftime('%Y-%m-%d'),
+                tz=tz,
+                ayanamsa=body.get('ayanamsa', 'lahiri'),
+            )
             canonical_planets = {}
             for planet_name, planet in canonical_chart.get('planets', {}).items():
                 if not isinstance(planet, dict):

tests/test_commercial_domain_calculation_contract.py

@@ -77,3 +77,30 @@ def test_api_visible_chart_values_come_from_domain_service(monkeypatch: pytest.M
         assert rest["planets"][planet]["lon"] == pytest.approx(
             expected["planets"][planet]["lon"], abs=1e-8
         )
+
+
+def test_api_sade_sati_uses_domain_true_saturn_transit(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("JYOTISH_API_CHART_CACHE_TTL_SECONDS", "0")
+    monkeypatch.setenv("VEDASTRO_ENABLE_NETWORK", "0")
+    monkeypatch.setattr(
+        jyotish_api_server,
+        "_attach_vedastro_main_entry_overview",
+        lambda result, _birth: result,
+    )
+    request = {**BIRTH, "node_mode": "true", "transit_date": "2026-07-11"}
+    chart = calculation_service.compute_chart(request)
+    expected = calculation_service.compute_sade_sati(
+        moon_degree=chart["planets"]["Moon"]["lon"],
+        asc_degree=chart["ascendant"]["lon"],
+        reference_date="2026-07-11",
+        tz=BIRTH["tz"],
+        ayanamsa=BIRTH["ayanamsa"],
+    )
+
+    rest = JyotishAPIHandler.__new__(JyotishAPIHandler)._compute_chart_sync(request)
+
+    assert rest["sade_sati"]["transit_saturn_lon"] == pytest.approx(
+        expected["transit_saturn_lon"], abs=1e-8
+    )
+    assert rest["sade_sati"]["provenance"]["data_layer"] == "true_transit_positions"
+    assert rest["sade_sati"]["calculation_contract"]["algorithm"] == "sade_sati_true_saturn_transit"