feat: enforce agent routing and persist restart state

Task 4: stale room blocking + agent_id binding
- MatrixBot._check_agent_routing: blocks normal messages when user has no
  selected agent or room is bound to a different agent
- agent_routing_enabled flag on MatrixRuntime activates the check only
  in real multi-agent mode (RoutedPlatformClient)
- make_handle_new_chat now writes agent_id into new room metadata when
  user already has a selected agent

Task 5: durable restart state tests
- test_restart_persistence.py proves selected_agent_id, room agent_id,
  platform_chat_id, and the sequence counter all survive SQLiteStore
  close/reopen; also covers clean startup with no prior state

tests/adapter/matrix/test_restart_persistence.py

@@ -0,0 +1,75 @@
+from __future__ import annotations
+
+import pytest
+
+from core.store import SQLiteStore
+from adapter.matrix.store import (
+    PLATFORM_CHAT_SEQ_KEY,
+    get_room_meta,
+    get_selected_agent_id,
+    next_platform_chat_id,
+    set_room_meta,
+    set_selected_agent_id,
+)
+
+
+async def test_selected_agent_id_survives_restart(tmp_path):
+    db = str(tmp_path / "state.db")
+    store = SQLiteStore(db)
+    await set_selected_agent_id(store, "@alice:example.org", "agent-2")
+
+    store2 = SQLiteStore(db)
+    assert await get_selected_agent_id(store2, "@alice:example.org") == "agent-2"
+
+
+async def test_room_agent_id_and_platform_chat_id_survive_restart(tmp_path):
+    db = str(tmp_path / "state.db")
+    store = SQLiteStore(db)
+    await set_room_meta(store, "!room:example.org", {
+        "room_type": "chat",
+        "agent_id": "agent-1",
+        "platform_chat_id": "42",
+    })
+
+    store2 = SQLiteStore(db)
+    meta = await get_room_meta(store2, "!room:example.org")
+    assert meta is not None
+    assert meta["agent_id"] == "agent-1"
+    assert meta["platform_chat_id"] == "42"
+
+
+async def test_platform_chat_seq_survives_restart(tmp_path):
+    db = str(tmp_path / "state.db")
+    store = SQLiteStore(db)
+    assert await next_platform_chat_id(store) == "1"
+    assert await next_platform_chat_id(store) == "2"
+    assert await next_platform_chat_id(store) == "3"
+
+    store2 = SQLiteStore(db)
+    assert await next_platform_chat_id(store2) == "4"
+
+
+async def test_routing_state_survives_restart_and_routes_correctly(tmp_path):
+    db = str(tmp_path / "state.db")
+    store = SQLiteStore(db)
+    await set_selected_agent_id(store, "@bob:example.org", "agent-1")
+    await set_room_meta(store, "!convo:example.org", {
+        "room_type": "chat",
+        "agent_id": "agent-1",
+        "platform_chat_id": "10",
+    })
+
+    store2 = SQLiteStore(db)
+    selected = await get_selected_agent_id(store2, "@bob:example.org")
+    meta = await get_room_meta(store2, "!convo:example.org")
+    assert selected == "agent-1"
+    assert meta is not None
+    assert meta["agent_id"] == selected
+    assert meta["platform_chat_id"] == "10"
+
+
+async def test_missing_durable_store_starts_clean(tmp_path):
+    db = str(tmp_path / "brand_new.db")
+    store = SQLiteStore(db)
+    assert await get_selected_agent_id(store, "@nobody:example.org") is None
+    assert await get_room_meta(store, "!nonexistent:example.org") is None

tests/adapter/matrix/test_routing_enforcement.py

@@ -0,0 +1,105 @@
+from __future__ import annotations
+
+import pytest
+from unittest.mock import AsyncMock, MagicMock
+
+from adapter.matrix.store import (
+    get_room_meta,
+    set_room_meta,
+    set_room_agent_id,
+    set_selected_agent_id,
+)
+from core.protocol import IncomingCommand, OutgoingMessage
+from core.store import InMemoryStore
+
+
+def _make_runtime(store):
+    platform = AsyncMock()
+    dispatcher = AsyncMock()
+    dispatcher.dispatch.return_value = [OutgoingMessage(chat_id="!r:s", text="ok")]
+    runtime = MagicMock()
+    runtime.store = store
+    runtime.dispatcher = dispatcher
+    runtime.platform = platform
+    runtime.agent_routing_enabled = True
+    return runtime
+
+
+def _make_bot(store):
+    from adapter.matrix.bot import MatrixBot
+    client = MagicMock()
+    client.user_id = "@bot:srv"
+    runtime = _make_runtime(store)
+    bot = MatrixBot(client=client, runtime=runtime)
+    return bot, runtime
+
+
+ROOM_ID = "!room:srv"
+USER_ID = "@alice:srv"
+
+
+async def _send_message(bot, body):
+    from nio import RoomMessageText, MatrixRoom
+    room = MagicMock(spec=MatrixRoom)
+    room.room_id = ROOM_ID
+    event = MagicMock(spec=RoomMessageText)
+    event.sender = USER_ID
+    event.body = body
+    event.source = {}
+    bot._send_all = AsyncMock()
+    await bot.on_room_message(room, event)
+    return bot._send_all
+
+
+async def test_stale_room_blocks_normal_message():
+    store = InMemoryStore()
+    await set_room_meta(store, ROOM_ID, {"room_type": "chat", "matrix_user_id": USER_ID,
+                                          "platform_chat_id": "1", "agent_id": "agent-1"})
+    await set_selected_agent_id(store, USER_ID, "agent-2")
+    bot, runtime = _make_bot(store)
+    send_all = await _send_message(bot, "hello")
+    runtime.dispatcher.dispatch.assert_not_called()
+    args = send_all.call_args[0]
+    assert any("agent-1" in m.text and "!new" in m.text for m in args[1])
+
+
+async def test_stale_room_allows_commands():
+    store = InMemoryStore()
+    await set_room_meta(store, ROOM_ID, {"room_type": "chat", "matrix_user_id": USER_ID,
+                                          "platform_chat_id": "1", "agent_id": "agent-1"})
+    await set_selected_agent_id(store, USER_ID, "agent-2")
+    bot, runtime = _make_bot(store)
+    await _send_message(bot, "!help")
+    runtime.dispatcher.dispatch.assert_called_once()
+
+
+async def test_no_selected_agent_blocks_normal_message():
+    store = InMemoryStore()
+    await set_room_meta(store, ROOM_ID, {"room_type": "chat", "matrix_user_id": USER_ID,
+                                          "platform_chat_id": "1"})
+    bot, runtime = _make_bot(store)
+    send_all = await _send_message(bot, "hello")
+    runtime.dispatcher.dispatch.assert_not_called()
+    args = send_all.call_args[0]
+    assert any("!agent" in m.text for m in args[1])
+
+
+async def test_no_selected_agent_allows_commands():
+    store = InMemoryStore()
+    await set_room_meta(store, ROOM_ID, {"room_type": "chat", "matrix_user_id": USER_ID,
+                                          "platform_chat_id": "1"})
+    bot, runtime = _make_bot(store)
+    await _send_message(bot, "!agent")
+    runtime.dispatcher.dispatch.assert_called_once()
+
+
+async def test_unbound_room_binds_on_message_when_agent_selected():
+    store = InMemoryStore()
+    await set_room_meta(store, ROOM_ID, {"room_type": "chat", "matrix_user_id": USER_ID,
+                                          "platform_chat_id": "1"})
+    await set_selected_agent_id(store, USER_ID, "agent-1")
+    bot, runtime = _make_bot(store)
+    await _send_message(bot, "hello")
+    meta = await get_room_meta(store, ROOM_ID)
+    assert meta["agent_id"] == "agent-1"
+    runtime.dispatcher.dispatch.assert_called_once()