fix: Add additional methods in TaskUpdater (#378)

Small updates to TaskUpdater that I found useful while working on #338

Author: fjuma

server-common/src/main/java/io/a2a/server/tasks/TaskUpdater.java

@@ -32,11 +32,11 @@ private void updateStatus(TaskState taskState) {
         updateStatus(taskState, null, taskState.isFinal());
     }
 
-    private void updateStatus(TaskState taskState, Message message) {
+    public void updateStatus(TaskState taskState, Message message) {
         updateStatus(taskState, message, taskState.isFinal());
     }
 
-    private void updateStatus(TaskState state, Message message, boolean isFinal) {
+    public void updateStatus(TaskState state, Message message, boolean isFinal) {
         synchronized (stateLock) {
             // Check if we're already in a terminal state
             if (terminalStateReached.get()) {
@@ -62,6 +62,10 @@ public String getContextId() {
         return this.contextId;
     }
 
+    public String getTaskId() {
+        return this.taskId;
+    }
+
     public void addArtifact(List<Part<?>> parts) {
         addArtifact(parts, null, null, null);
     }