fix: resolve machine deletion failure after parts removal by nullifying orphaned FK references

src/api/machines.py

@@ -3,12 +3,18 @@ from uuid import UUID
 
 from fastapi import APIRouter, HTTPException, Depends, Path
 from pydantic import BaseModel
-from sqlalchemy import select, func
+from sqlalchemy import select, func, update
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import selectinload
 
 from src.database.config import get_db
-from src.database.models import Machine, EquipmentPart
+from src.database.models import (
+    Machine,
+    EquipmentPart,
+    InspectionTemplate,
+    InspectionTemplateItem,
+    Alarm,
+)
 from src.auth.models import TokenData
 from src.auth.dependencies import require_auth, verify_tenant_access
 
@@ -288,6 +294,29 @@ async def delete_machine(
             detail=f"활성 부품이 {parts_count}개 있어 삭제할 수 없습니다. 먼저 부품을 제거해주세요.",
         )
 
+    # Null out FKs in tables without cascade before deleting machine
+    part_ids_stmt = select(EquipmentPart.id).where(
+        EquipmentPart.machine_id == machine_id
+    )
+    await db.execute(
+        update(InspectionTemplateItem)
+        .where(InspectionTemplateItem.equipment_part_id.in_(part_ids_stmt))
+        .values(equipment_part_id=None)
+    )
+    await db.execute(
+        update(Alarm)
+        .where(Alarm.equipment_part_id.in_(part_ids_stmt))
+        .values(equipment_part_id=None)
+    )
+    await db.execute(
+        update(InspectionTemplate)
+        .where(InspectionTemplate.machine_id == machine_id)
+        .values(machine_id=None)
+    )
+    await db.execute(
+        update(Alarm).where(Alarm.machine_id == machine_id).values(machine_id=None)
+    )
+
     await db.delete(machine)
     await db.commit()