feat: FastAPI 配置 OpenAPI 文档分组

[lennney]

问题

FastAPI() 初始化时没有设置 openapi_tags，Swagger UI（/docs）上的端点没有分组，看起来很混乱。

修复方案

app = FastAPI(
    title="TicketPilot API",
    description="AI Customer Service Copilot API",
    version="1.0.0",
    openapi_tags=[
        {"name": "chat", "description": "聊天交互接口"},
        {"name": "tickets", "description": "工单处理接口"},
        {"name": "reviews", "description": "人工审核接口"},
        {"name": "evaluation", "description": "评估指标接口"},
        {"name": "health", "description": "健康检查"},
    ],
)

每个端点添加 tags=[...] 参数。

涉及文件

• src/ticketpilot/api/__init__.py
• src/ticketpilot/api/streaming.py

[lennney]

Fixed in PR #31: openapi_tags added to FastAPI init