fix: reverse Rahu degree in eight-karaka ranking

(cherry picked from commit 197672e3f1c5d06fe44f0da196d36f6cf4a856cf)

scripts/jaimini.py

@@ -132,21 +132,29 @@ def calc_chara_karaka_7(planet_degrees: Dict[str, float]) -> Dict:
 
 
 def calc_chara_karaka_8(planet_degrees: Dict[str, float]) -> Dict:
-    """计算8星制Chara Karaka（含Rahu，Ketu排除）。"""
+    """计算8星制Chara Karaka（含Rahu，Ketu排除）。
+
+    8星制按传统规则以 ``30 - Rahu 的星座内度数`` 排序；其余行星
+    使用原始星座内度数。原始值和排序值都保留在结果中，便于审计。
+    """
     planets = {}
     for pname, deg in planet_degrees.items():
         if pname == 'Ketu':
             continue
-        planets[pname] = deg
-    sorted_planets = sorted(planets.items(), key=lambda x: x[1], reverse=True)
+        raw_degree = float(deg) % 30.0
+        effective_degree = (30.0 - raw_degree) % 30.0 if pname == 'Rahu' else raw_degree
+        planets[pname] = (raw_degree, effective_degree)
+    sorted_planets = sorted(planets.items(), key=lambda x: x[1][1], reverse=True)
     results = {}
-    for rank, (pname, deg) in enumerate(sorted_planets, 1):
+    for rank, (pname, (raw_degree, effective_degree)) in enumerate(sorted_planets, 1):
         if rank > 8:
             break
         karaka = KARAKA_8[rank]
         results[karaka] = {
             'planet': pname,
-            'degree_in_sign': round(deg, 4),
+            'degree_in_sign': round(raw_degree, 4),
+            'effective_degree_in_sign': round(effective_degree, 4),
+            'rahu_reverse_applied': pname == 'Rahu',
             'rank': rank,
             'domain': KARAKA_DOMAINS.get(karaka, ''),
             'cn_name': KARAKA_CN.get(karaka, karaka),

tests/test_jaimini.py

@@ -89,6 +89,17 @@ class TestCharaKaraka8:
         planets = [v['planet'] for v in result['karaka_table_8'].values()]
         assert 'Ketu' not in planets
 
+    def test_rahu_uses_reverse_degree_for_eight_karaka_ranking(self):
+        degrees = {
+            'Sun': 10.0, 'Moon': 11.0, 'Mars': 12.0, 'Mercury': 13.0,
+            'Jupiter': 14.0, 'Venus': 15.0, 'Saturn': 16.0, 'Rahu': 29.0,
+        }
+        result = calc_chara_karaka_8(degrees)
+        rahu = next(row for row in result['karaka_table_8'].values() if row['planet'] == 'Rahu')
+        assert rahu['degree_in_sign'] == 29.0
+        assert rahu['effective_degree_in_sign'] == 1.0
+        assert rahu['rahu_reverse_applied'] is True
+
 
 # ── Arudha Pada Tests ──────────────────────────────────────────────