fix(평면): 평면 비탈 끝 · B07 계획평면도 = 벽 측점 횡단 최종 모양이 땅과 만나는 점 (PLAN 578-2 · 요구 438 · 439)

- B06 STRUCTURE_ROW_KEYS · 서버 _AREA_KEYS 에 slope_end_left_m · slope_end_right_m — 벽 트림 측점만 · 트림 사면 → 단마다 벽 앞 → 사이 성토부선 윤곽이 처음 땅에 닿는 오프셋
- 평면 발자국 finalSlopeEnd · B07 final_slope_end(짝) — 얹은 값 먼저 · 없으면 설계선 끝(구조물 없는 측점 그대로)
- 시험 test_578_2_plan_slope_end 새로 · test_346_2 거울에 벽 측점 줄

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

B07_DesignDetail/B07_DesignDetail_Router_Support_Plan.py

@@ -42,10 +42,9 @@ from B07_DesignDetail.B07_DesignDetail_Engine_Cad_PlanKinds import (
     curve_pieces,
     route_frame,
     side_is_cut,
-    slope_end,
     slope_pieces,
 )
-from B07_DesignDetail.B07_DesignDetail_Engine_Cad_PlanSlope import tick_step_m
+from B07_DesignDetail.B07_DesignDetail_Engine_Cad_PlanSlope import final_slope_end, tick_step_m
 from B07_DesignDetail.B07_DesignDetail_Router_Support_Basin import (
     _chunk_route,
     _hillshade_for_box,
@@ -375,13 +374,13 @@ def slope_records(
             right_edge = float(edges["right"]["offset_m"])
         except (KeyError, TypeError, ValueError):
             continue
-        line, samples = (design or {}).get("design_line") or [], source.get("samples") or []
+        samples = source.get("samples") or []
         record: dict[str, Any] = {
             "chainage_m": float(chainage),
             "left_edge_m": left_edge,
-            "left_end_m": slope_end(line, samples, left_edge, "left"),
+            "left_end_m": final_slope_end(design, samples, left_edge, "left"),
             "right_edge_m": right_edge,
-            "right_end_m": slope_end(line, samples, right_edge, "right"),
+            "right_end_m": final_slope_end(design, samples, right_edge, "right"),
         }
         for side in ("left", "right"):
             elevation = edges[side].get("elevation_m")