feat(webui): add initial webui with websocket chat flow

tests/agent/test_session_delete.py

@@ -0,0 +1,65 @@
+"""Tests for SessionManager.delete_session and read_session_file."""
+
+from pathlib import Path
+
+from nanobot.session.manager import Session, SessionManager
+
+
+def _seed(workspace: Path, key: str = "telegram:abc") -> SessionManager:
+    sm = SessionManager(workspace)
+    session = Session(key=key)
+    session.add_message("user", "hello")
+    session.add_message("assistant", "hi back")
+    sm.save(session)
+    return sm
+
+
+def test_delete_session_removes_file_and_invalidates_cache(tmp_path: Path) -> None:
+    sm = _seed(tmp_path, "telegram:abc")
+    file_path = sm._get_session_path("telegram:abc")
+    assert file_path.exists()
+    # Populate cache as a real consumer would.
+    cached = sm.get_or_create("telegram:abc")
+    assert cached.messages
+
+    assert sm.delete_session("telegram:abc") is True
+    assert not file_path.exists()
+    # Subsequent get_or_create returns a fresh, empty Session (no stale cache).
+    fresh = sm.get_or_create("telegram:abc")
+    assert fresh.messages == []
+
+
+def test_delete_session_returns_false_when_missing(tmp_path: Path) -> None:
+    sm = SessionManager(tmp_path)
+    assert sm.delete_session("nope:none") is False
+
+
+def test_read_session_file_returns_metadata_and_messages(tmp_path: Path) -> None:
+    sm = _seed(tmp_path, "telegram:abc")
+    data = sm.read_session_file("telegram:abc")
+    assert data is not None
+    assert data["key"] == "telegram:abc"
+    assert isinstance(data["messages"], list)
+    assert [m["role"] for m in data["messages"]] == ["user", "assistant"]
+    assert data["created_at"]
+    assert data["updated_at"]
+
+
+def test_read_session_file_does_not_populate_cache(tmp_path: Path) -> None:
+    sm = _seed(tmp_path, "telegram:abc")
+    sm.invalidate("telegram:abc")
+    assert "telegram:abc" not in sm._cache
+    sm.read_session_file("telegram:abc")
+    assert "telegram:abc" not in sm._cache
+
+
+def test_read_session_file_missing(tmp_path: Path) -> None:
+    sm = SessionManager(tmp_path)
+    assert sm.read_session_file("nope:none") is None
+
+
+def test_safe_key_matches_internal_path(tmp_path: Path) -> None:
+    sm = SessionManager(tmp_path)
+    key = "telegram:abc/def"
+    expected = sm._get_session_path(key).name
+    assert SessionManager.safe_key(key) + ".jsonl" == expected