fix(api): 修復 Repository 層 lint 錯誤

- 移除未使用的 imports
- 修正 import 排序

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/api/src/repositories/__init__.py

@@ -13,11 +13,6 @@ Phase 16 R3: 抽取 Repository 層
 建立者: Claude Code (Phase 16 架構重構)
 """
 
-from src.repositories.interfaces import (
-    IApprovalRepository,
-    IIncidentRepository,
-    ITimelineRepository,
-)
 from src.repositories.approval_repository import (
     ApprovalDBRepository,
     get_approval_repository,
@@ -26,6 +21,11 @@ from src.repositories.incident_repository import (
     IncidentDBRepository,
     get_incident_repository,
 )
+from src.repositories.interfaces import (
+    IApprovalRepository,
+    IIncidentRepository,
+    ITimelineRepository,
+)
 
 __all__ = [
     # Interfaces

apps/api/src/repositories/approval_repository.py

@@ -16,13 +16,12 @@ from typing import Any
 from uuid import UUID
 
 import structlog
-from sqlalchemy import select, update
+from sqlalchemy import select
 
 from src.db.base import get_db_context
 from src.db.models import ApprovalRecord
 from src.models.approval import (
     ApprovalRequest,
-    ApprovalRequestCreate,
     ApprovalStatus,
     BlastRadius,
     DataImpact,

apps/api/src/repositories/interfaces.py

@@ -13,7 +13,6 @@ Phase 16 R3: Repository 層 Protocol 介面
 建立者: Claude Code (Phase 16 架構重構)
 """
 
-from datetime import datetime
 from typing import Protocol, runtime_checkable
 from uuid import UUID