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。

scripts/ayanamsa_utils.py

@@ -132,3 +132,20 @@ def temporary_ayanamsa(name: Any = None, swe_module: Any = None) -> Iterator[str
 def sidereal_flags(swe_module: Any, ayanamsa_name: Any = None) -> int:
     apply_ayanamsa(ayanamsa_name, swe_module)
     return getattr(swe_module, 'FLG_SWIEPH', 2) | getattr(swe_module, 'FLG_SIDEREAL', 65536)
+
+
+def sidereal_ayanamsa_degrees(jd_ut: float, swe_module: Any = None, flags: int | None = None) -> float:
+    """Ayanamsa that FLG_SIDEREAL subtracts for these flags.
+
+    ``get_ayanamsa`` and ``get_ayanamsa_ut`` omit nutation. Apparent tropical
+    positions include it, so that subtraction shifts every longitude by Δψ.
+    """
+    module = swe_module or swe
+    if module is None:
+        raise RuntimeError("swisseph is not available")
+    if flags is None:
+        flags = getattr(module, "FLG_SWIEPH", 2)
+    raw = module.get_ayanamsa_ex_ut(float(jd_ut), int(flags))
+    if isinstance(raw, (tuple, list)):
+        return float(raw[1])
+    return float(raw)