fix(api): 修復全部 lint 錯誤 (ruff --fix)

- Import sorting (I001)
- Unused imports (F401)
- f-string without placeholders (F541)
- Loop variable unused (B007)
- zip() strict parameter (B905)
- Exception chaining (B904)
- collections.abc imports (UP035)

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

apps/api/src/models/playbook.py

@@ -12,13 +12,15 @@ Phase 7.1: 資料模型定義
 - 支援 PostgreSQL + Redis 雙層儲存
 """
 
-from datetime import UTC, datetime
+from datetime import datetime
 from enum import Enum
 from typing import Any
 from uuid import uuid4
 
 from pydantic import BaseModel, ConfigDict, Field
 
+from src.utils.timezone import now_taipei
+
 # =============================================================================
 # Enums
 # =============================================================================
@@ -123,8 +125,8 @@ class RepairStep(BaseModel):
 
 
 def generate_playbook_id() -> str:
-    """生成 Playbook ID"""
-    return f"PB-{datetime.now(UTC).strftime('%Y%m%d')}-{uuid4().hex[:6].upper()}"
+    """生成 Playbook ID (台北時區)"""
+    return f"PB-{now_taipei().strftime('%Y%m%d')}-{uuid4().hex[:6].upper()}"
 
 
 class Playbook(BaseModel):
@@ -195,8 +197,8 @@ class Playbook(BaseModel):
     notes: str | None = Field(None, description="人工補充說明")
 
     # === 時間軸 ===
-    created_at: datetime = Field(default_factory=lambda: datetime.now(UTC))
-    updated_at: datetime = Field(default_factory=lambda: datetime.now(UTC))
+    created_at: datetime = Field(default_factory=now_taipei)
+    updated_at: datetime = Field(default_factory=now_taipei)
 
     model_config = ConfigDict(extra="ignore")