feat(auth): add org/dept/position management, user page, and Phase 2 completion

Complete Phase 2 identity & authentication module:
- Organization CRUD with tree structure (parent_id + materialized path)
- Department CRUD nested under organizations with tree support
- Position CRUD nested under departments
- User management page with table, create/edit modal, role assignment
- Organization architecture page with 3-panel tree layout
- Frontend API layer for orgs/depts/positions
- Sidebar navigation updated with organization menu item
- Fix parse_ttl edge case for strings ending in 'd' (e.g. "invalid")

crates/erp-auth/src/dto.rs

@@ -163,6 +163,14 @@ pub struct CreateDepartmentReq {
     pub sort_order: Option<i32>,
 }
 
+#[derive(Debug, Deserialize, ToSchema)]
+pub struct UpdateDepartmentReq {
+    pub name: Option<String>,
+    pub code: Option<String>,
+    pub manager_id: Option<Uuid>,
+    pub sort_order: Option<i32>,
+}
+
 // --- Position DTOs ---
 
 #[derive(Debug, Serialize, ToSchema)]
@@ -183,3 +191,11 @@ pub struct CreatePositionReq {
     pub level: Option<i32>,
     pub sort_order: Option<i32>,
 }
+
+#[derive(Debug, Deserialize, ToSchema)]
+pub struct UpdatePositionReq {
+    pub name: Option<String>,
+    pub code: Option<String>,
+    pub level: Option<i32>,
+    pub sort_order: Option<i32>,
+}