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-plugin/src/entity/plugin.rs

@@ -0,0 +1,54 @@
+use sea_orm::entity::prelude::*;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Debug, PartialEq, DeriveEntityModel, Serialize, Deserialize)]
+#[sea_orm(table_name = "plugins")]
+pub struct Model {
+    #[sea_orm(primary_key, auto_increment = false)]
+    pub id: Uuid,
+    pub tenant_id: Uuid,
+    pub name: String,
+    #[sea_orm(column_name = "plugin_version")]
+    pub plugin_version: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub description: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub author: Option<String>,
+    pub status: String,
+    pub manifest_json: serde_json::Value,
+    #[serde(skip)]
+    pub wasm_binary: Vec<u8>,
+    pub wasm_hash: String,
+    pub config_json: serde_json::Value,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub error_message: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub installed_at: Option<DateTimeUtc>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub enabled_at: Option<DateTimeUtc>,
+    pub created_at: DateTimeUtc,
+    pub updated_at: DateTimeUtc,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub created_by: Option<Uuid>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub updated_by: Option<Uuid>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub deleted_at: Option<DateTimeUtc>,
+    pub version: i32,
+}
+
+#[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
+pub enum Relation {
+    #[sea_orm(has_many = "super::plugin_entity::Entity")]
+    PluginEntity,
+    #[sea_orm(has_many = "super::plugin_event_subscription::Entity")]
+    PluginEventSubscription,
+}
+
+impl Related<super::plugin_entity::Entity> for Entity {
+    fn to() -> RelationDef {
+        Relation::PluginEntity.def()
+    }
+}
+
+impl ActiveModelBehavior for ActiveModel {}