fix(qizheng): pass school options into the vendored chart and stabilize gates

BUG-710: call getSevenGovernorsChart with ketuMode/siderealMode so
calculation.ketu_mode is the engine school, not the request echo.
BUG-711: stop forbidding /ephemeris in the sidebar contract.
BUG-712: compare ephemeris event longitudes at 6 decimals and fail
closed when the golden is missing.

frontend/src/lib/chart-view-mapper.ts

@@ -599,7 +599,10 @@ function mapQizheng(raw: Record<string, unknown> | null): ChartViewQizhengOk | C
   return {
     status: "ok",
     coordinateSystem: text(raw.coordinate_system) ?? "qizheng_mansion_degrees_from_jiao",
-    ketuMode: text(raw.ketu_mode) ?? text(raw.ketuMode) ?? "unspecified",
+    ketuMode: text(record(raw.calculation)?.engine_ketu_mode)
+      ?? text(record(raw.chart)?.ketu_mode)
+      ?? text(raw.ketuMode)
+      ?? "unspecified",
     boundary: COORDINATE_BOUNDARY.qizheng,
     palaces,
     bodies,