fix: Use incremental ID

heromodels/src/models/calendar/calendar.rs

@@ -142,10 +142,16 @@ impl Calendar {
     /// Creates a new calendar with auto-generated ID
     ///
     /// # Arguments
+    /// * `id` - Optional ID for the calendar (use None for auto-generated ID)
     /// * `name` - Name of the calendar
-    pub fn new(name: impl ToString) -> Self {
+    pub fn new(id: Option<u32>, name: impl ToString) -> Self {
+        let mut base_data = BaseModelData::new();
+        if let Some(id) = id {
+            base_data.update_id(id);
+        }
+
         Self {
-            base_data: BaseModelData::new(),
+            base_data,
             name: name.to_string(),
             description: None,
             events: Vec::new(),