test(ai): 添加 erp-ai 集成测试 — 14 个测试覆盖 3 个 service

- PromptService: 创建/查询/列表筛选/激活版本切换/回滚/跨租户隔离/未找到错误 (7)
- UsageService: 日志记录/概览/按类型聚合/跨租户隔离 (4)
- AnalysisService: 完成分析/失败分析/缓存查找/列表筛选 (3)
- 使用 MockProvider 替代真实 AI 调用

crates/erp-server/Cargo.toml

@@ -44,3 +44,8 @@ erp-plugin = { workspace = true }
 erp-workflow = { workspace = true }
 erp-core = { workspace = true }
 erp-dialysis = { workspace = true }
+erp-ai = { workspace = true }
+async-trait.workspace = true
+futures.workspace = true
+sha2.workspace = true
+hex.workspace = true