fix(ephemeris): include nutation in the sidereal frame

恒星黄道改为与 Swiss Ephemeris FLG_SIDEREAL 同一套含章动岁差。
产品默认路径不再用平岁差去减含章动的视位置。上升和宫头用同一个岁差。
校正身份升到 rectification-v5-matrix-scoring-12。
BUG-1275。未推送，未部署。v5 先验头名三格下降 1.3 个百分点，不调参。

frontend/src/lib/rectification-agentic/v9/engine-client.ts

@@ -1071,7 +1071,7 @@ export async function runV9Diagnostics(input: {
 // Keep the receipt default aligned with Python's ALGORITHM_VERSION; persisted
 // receipts retain their original identity (this is not a Skill/open gate).
 export const v9EngineVersion = (): string =>
-  process.env.RECTIFICATION_ENGINE_VERSION?.trim() || "rectification-v5-matrix-scoring-11";
+  process.env.RECTIFICATION_ENGINE_VERSION?.trim() || "rectification-v5-matrix-scoring-12";
 
 export type V9RangeReading = Readonly<{
   stableThemes: readonly string[];