feat(tkeg): 자재 비교 저장 활성화 + 프로젝트 수정 활동 로그 구현

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tkeg/api/app/routers/material_comparison.py

@@ -52,14 +52,16 @@ async def compare_material_revisions(
             db, current_file, previous_file, job_no
         )
         
-        # 4. 결과 저장 (선택사항) - 임시로 비활성화
+        # 4. 결과 저장
         comparison_id = None
-        # TODO: 저장 기능 활성화
-        # if save_result and previous_file and previous_revision:
-        #     comparison_id = await save_comparison_result(
-        #         db, job_no, current_revision, previous_revision,
-        #         current_file["id"], previous_file["id"], comparison_result
-        #     )
+        if save_result and previous_file and previous_revision:
+            try:
+                comparison_id = await save_comparison_result(
+                    db, job_no, current_revision, previous_revision,
+                    current_file["id"], previous_file["id"], comparison_result
+                )
+            except Exception as e:
+                logger.warning(f"비교 결과 저장 실패 (비교 자체는 성공): {e}")
         
         return {
             "success": True,