feat: add thread info and status reads

tests/test_app.py

@@ -15,6 +15,25 @@ def test_app_facade_with_memory():
     assert app.has_unread(t.id, bob) is False
 
 
+def test_app_thread_info_and_read_state():
+    app = App(store=InMemoryStore())
+    alice = app.get_or_create_agent("Alice")
+    bob = app.get_or_create_agent("Bob")
+    thread = app.create_thread(alice, bob)
+    latest = app.append(thread.id, alice, "hello")
+
+    info = app.get_thread_info(thread.id)
+    state = app.get_thread_read_state(thread.id, bob)
+
+    assert info is not None
+    assert info.latest_message == latest
+    assert info.message_count == 1
+    assert state.cursor_seq == 0
+    assert state.latest_seq == 1
+    assert state.unread_count == 1
+    assert state.unread_from_others_count == 1
+
+
 def test_app_delete_account():
     from agentmsgs.core.app import App
     from agentmsgs.stores.memory import InMemoryStore