ModelTranslator: 新增 pick_best_candidate——过门且岛数最少者择优

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Tools/ModelTranslator/bl_decimate.py

@@ -38,6 +38,16 @@ def uvpm_mode_label(base, applied):
     return base + "+uvpm" if applied else base
 
 
+def pick_best_candidate(candidates):
+    """从候选 UV 指标 dict 列表选过质量门且岛数最少者；无过门候选返回 None。
+    每个 candidate 至少含 flipped/overlap/islands。"""
+    passing = [c for c in candidates
+               if uv_gate_ok(c["flipped"], c["overlap"])]
+    if not passing:
+        return None
+    return min(passing, key=lambda c: c["islands"])
+
+
 def count_islands(n_faces, adjacent_pairs):
     """union-find 数 UV 岛：n_faces 个面，adjacent_pairs 为 UV 连续的面索引对。"""
     parent = list(range(n_faces))