feat: initialize Nuanji (Warm Notes) project

- Base platform from base.git (ERP base: auth, core, config, message, workflow, plugin)
- Created erp-diary module skeleton (lib.rs, dto.rs, error.rs, event.rs, state.rs)
- Integrated erp-diary into workspace and erp-server
- Added DiaryModule registration in main.rs
- Added DiaryState FromRef in state.rs
- Diary routes mounted (empty routes, ready for implementation)
- Product design spec v1.2 preserved in docs/
- Implementation plan preserved in plans/

Cargo check: OK
Cargo test: OK (78+ base tests passing)

crates/erp-core/src/aggregate.rs

@@ -0,0 +1,38 @@
+//! 聚合查询容错工具
+//!
+//! 仪表盘等聚合统计端点通常包含多个独立子查询。
+//! 单个子查询失败不应导致整个接口 500。
+//! `safe_aggregate` 让每个子查询独立容错，失败时返回默认值并记录警告日志。
+
+use std::future::Future;
+
+/// 执行一个子查询，失败时返回 `T::default()` 并记录警告日志。
+///
+/// # 使用场景
+///
+/// 仪表盘统计 API 聚合多个指标（患者数/咨询数/随访数等），
+/// 任一子查询失败不应阻塞其他指标返回。
+///
+/// # 示例
+///
+/// ```rust,ignore
+/// let patients = safe_aggregate(
+///     stats_service::get_patient_statistics(&state, tenant_id),
+///     "患者统计",
+/// ).await;
+/// ```
+pub async fn safe_aggregate<T: Default, E: std::fmt::Display>(
+    fut: impl Future<Output = Result<T, E>>,
+    label: &str,
+) -> T {
+    match fut.await {
+        Ok(v) => {
+            tracing::debug!("聚合子查询 [{label}] 成功");
+            v
+        }
+        Err(e) => {
+            tracing::warn!("聚合子查询 [{label}] 失败，使用默认值: {e}");
+            T::default()
+        }
+    }
+}