feat: add thread info and status reads

tests/test_types.py

@@ -1,7 +1,7 @@
 import datetime
 import uuid
 
-from agentmsgs.core.types import Agent, Thread
+from agentmsgs.core.types import Agent, Message, Thread, ThreadInfo, ThreadReadState
 
 
 def test_agent_identity_on_id_not_name():
@@ -36,3 +36,28 @@ def test_thread_multiple_with_same_participants_allowed():
     )
     assert t1 != t2
     assert t1.participants == t2.participants
+
+
+def test_thread_info_and_read_state_hold_derived_data():
+    now = datetime.datetime.now(datetime.UTC)
+    alice = Agent(id=uuid.uuid4(), name="Alice")
+    bob = Agent(id=uuid.uuid4(), name="Bob")
+    thread = Thread(
+        id=uuid.uuid4(), participants=frozenset({alice, bob}), created_at=now
+    )
+    latest = Message(
+        id=uuid.uuid4(), sender=bob, content="hello", seq=1, ts=now
+    )
+    info = ThreadInfo(thread=thread, message_count=1, latest_message=latest)
+    state = ThreadReadState(
+        agent=alice,
+        cursor_seq=0,
+        latest_seq=1,
+        unread_count=1,
+        unread_from_others_count=1,
+    )
+
+    assert info.thread == thread
+    assert info.latest_message == latest
+    assert state.agent == alice
+    assert state.unread_from_others_count == 1