refactor(B04): B04_wf1_Surface -> B04_PreProcess 전면 개명

- 폴더·내부 파일 51개 접두사 개명 (git mv, 이력 보존)
- 저장소 전체 참조 치환 67파일: import 경로, 라우트 슬러그(b04-preprocess),
  라우트 키(B04_PREPROCESS), storage 경로 상수, locale, SQL 주석
- 로직 변경 없음 (기계적 치환). typecheck·백엔드 import 검증 통과

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

B04_PreProcess/B04_PreProcess_Service.py

@@ -0,0 +1,54 @@
+"""B04 지표면 모델 확정 서비스."""
+
+from typing import Any
+from uuid import UUID
+
+import aiomysql
+
+from B04_PreProcess.B04_PreProcess_Repository import (
+    confirm_surface_model,
+    list_surface_models,
+)
+from common_util.common_util_surface_confirmation import (
+    merge_surface_confirmation_params,
+)
+from common_util.common_util_workflow_state import complete_stage
+
+
+async def find_surface_model_for_selection(
+    connection: aiomysql.Connection,
+    project_id: UUID,
+    selection: dict[str, Any],
+) -> int:
+    """필터·표현 기본값과 일치하는 COMPLETE 모델 ID를 찾는다."""
+    for model in await list_surface_models(connection, project_id):
+        generation_params = model.get("generation_params") or {}
+        if (
+            model["status"] == "COMPLETE"
+            and model["model_type"].lower() == str(selection["method"]).lower()
+            and str(generation_params.get("source_filter", "")).lower()
+            == str(selection["source_filter"]).lower()
+        ):
+            return int(model["id"])
+    raise LookupError(
+        "자동 확정 기본값과 일치하는 지표면 모델이 없습니다: "
+        f"filter={selection['source_filter']}, method={selection['method']}"
+    )
+
+
+async def confirm_surface_selection(
+    connection: aiomysql.Connection,
+    project_id: UUID,
+    model_id: int,
+    selection: dict[str, Any],
+) -> dict[str, Any]:
+    """모델 확정, 선택값 스냅샷, WF1 완료를 현재 트랜잭션에서 처리한다."""
+    await confirm_surface_model(connection, project_id, model_id)
+    normalized = await merge_surface_confirmation_params(
+        connection,
+        str(project_id),
+        selection,
+    )
+    async with connection.cursor() as cursor:
+        await complete_stage(cursor, str(project_id), 1)
+    return normalized