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/lib.rs

@@ -0,0 +1,19 @@
+pub mod aggregate;
+pub mod audit;
+pub mod audit_service;
+pub mod crypto;
+pub mod entity;
+pub mod error;
+pub mod events;
+pub mod module;
+pub mod rbac;
+pub mod request_info;
+pub mod sanitize;
+pub mod sea_orm_ext;
+pub mod types;
+
+#[cfg(test)]
+pub mod test_helpers;
+
+// 便捷导出
+pub use module::{ModuleContext, ModuleType, PermissionDescriptor};