feat(wm-revenue): #54 客服工作台+水费查询+语音自助
- Entity: CsWorkItem, VoiceCallRecord
- DTO: CsWorkbenchStats, BillQueryResult, VoiceMenuResponse
- Mapper: CsWorkItemMapper, VoiceCallRecordMapper
- Service: CsWorkbenchService, BillQueryService, VoiceQueryService
- Controller: CsWorkbenchController(9端点), BillQueryController(5端点), VoiceController(7端点)
- DDL: V_cs_workbench.sql (2表+索引)
- Test: CsWorkbenchTest (10个测试用例)
