feat(server): integrate AppState, ModuleRegistry, health check, and graceful shutdown

- Add AppState with DB, Config, EventBus, ModuleRegistry via Axum State
- ModuleRegistry now uses Arc for Clone support, builder-pattern register()
- Add /api/v1/health endpoint returning status, version, registered modules
- Add graceful shutdown on CTRL+C / SIGTERM
- erp-common utils: ID generation, timestamp helpers, code generator with tests
- Config structs now derive Clone for state sharing
- Update wiki to reflect Phase 1 completion

crates/erp-server/src/state.rs

@@ -0,0 +1,23 @@
+use axum::extract::FromRef;
+use sea_orm::DatabaseConnection;
+
+use crate::config::AppConfig;
+use erp_core::events::EventBus;
+use erp_core::module::ModuleRegistry;
+
+/// Axum 共享应用状态
+/// 所有 handler 通过 State<AppState> 获取数据库连接、配置等
+#[derive(Clone)]
+pub struct AppState {
+    pub db: DatabaseConnection,
+    pub config: AppConfig,
+    pub event_bus: EventBus,
+    pub module_registry: ModuleRegistry,
+}
+
+/// 允许 handler 直接提取子字段
+impl FromRef<AppState> for DatabaseConnection {
+    fn from_ref(state: &AppState) -> Self {
+        state.db.clone()
+    }
+}