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-server/Cargo.toml

@@ -0,0 +1,50 @@
+[package]
+name = "erp-server"
+version.workspace = true
+edition.workspace = true
+
+[[bin]]
+name = "erp-server"
+path = "src/main.rs"
+
+[dependencies]
+erp-core.workspace = true
+tokio.workspace = true
+axum.workspace = true
+tower.workspace = true
+tower-http.workspace = true
+tracing.workspace = true
+tracing-subscriber.workspace = true
+config.workspace = true
+sea-orm.workspace = true
+sqlx.workspace = true
+redis.workspace = true
+utoipa.workspace = true
+serde_json.workspace = true
+serde.workspace = true
+erp-server-migration = { path = "migration" }
+erp-auth.workspace = true
+erp-config.workspace = true
+erp-workflow.workspace = true
+erp-message.workspace = true
+erp-plugin.workspace = true
+erp-diary.workspace = true
+anyhow.workspace = true
+uuid.workspace = true
+chrono.workspace = true
+moka = { version = "0.12", features = ["sync"] }
+metrics.workspace = true
+metrics-exporter-prometheus.workspace = true
+hmac = "0.12"
+sha2 = "0.10"
+hex = "0.4"
+
+[dev-dependencies]
+erp-auth = { workspace = true }
+erp-plugin = { workspace = true }
+erp-workflow = { workspace = true }
+erp-core = { workspace = true }
+async-trait.workspace = true
+futures.workspace = true
+sha2.workspace = true
+hex.workspace = true