feat: handle TaskCreated hook event (closes #254)

src-tauri/src/types.rs

@@ -332,6 +332,18 @@ pub struct FileChangedEvent {
     pub conversation_id: Option<String>,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct TaskCreatedEvent {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub task_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub description: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub parent_tool_use_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub conversation_id: Option<String>,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct AgentStartEvent {
     pub tool_use_id: String,
@@ -803,4 +815,49 @@ mod tests {
         assert!(serialized.contains("\"file\":\"/tmp/test.txt\""));
         assert!(!serialized.contains("conversation_id"));
     }
+
+    #[test]
+    fn test_task_created_event_serialization() {
+        let event = TaskCreatedEvent {
+            task_id: Some("task-abc123".to_string()),
+            description: Some("Explore the codebase".to_string()),
+            parent_tool_use_id: Some("toolu_xyz".to_string()),
+            conversation_id: Some("conv-abc".to_string()),
+        };
+
+        let serialized = serde_json::to_string(&event).unwrap();
+        assert!(serialized.contains("\"task_id\":\"task-abc123\""));
+        assert!(serialized.contains("\"description\":\"Explore the codebase\""));
+        assert!(serialized.contains("\"parent_tool_use_id\":\"toolu_xyz\""));
+        assert!(serialized.contains("\"conversation_id\":\"conv-abc\""));
+    }
+
+    #[test]
+    fn test_task_created_event_omits_none_fields() {
+        let event = TaskCreatedEvent {
+            task_id: None,
+            description: None,
+            parent_tool_use_id: None,
+            conversation_id: None,
+        };
+
+        let serialized = serde_json::to_string(&event).unwrap();
+        assert_eq!(serialized, "{}");
+    }
+
+    #[test]
+    fn test_task_created_event_partial_fields() {
+        let event = TaskCreatedEvent {
+            task_id: Some("task-001".to_string()),
+            description: None,
+            parent_tool_use_id: None,
+            conversation_id: None,
+        };
+
+        let serialized = serde_json::to_string(&event).unwrap();
+        assert!(serialized.contains("\"task_id\":\"task-001\""));
+        assert!(!serialized.contains("description"));
+        assert!(!serialized.contains("parent_tool_use_id"));
+        assert!(!serialized.contains("conversation_id"));
+    }
 }