Fix WebUI startup blocking on slow gateway routes

tests/utils/test_webui_workspaces.py

@@ -7,8 +7,8 @@ from nanobot.webui.workspaces import (
     read_webui_default_access_mode,
     read_webui_workspace_state,
     webui_workspace_state_path,
-    write_webui_default_access_mode,
     workspaces_payload,
+    write_webui_default_access_mode,
 )
 
 
@@ -152,3 +152,32 @@ def test_webui_default_access_does_not_override_explicit_session_scope(tmp_path,
 
     assert scope.project_path == project.resolve()
     assert scope.access_mode == "full"
+
+
+def test_scope_for_session_key_reads_metadata_without_full_history(
+    tmp_path,
+    monkeypatch,
+) -> None:
+    monkeypatch.setattr("nanobot.webui.workspaces.get_webui_dir", lambda: tmp_path / "webui")
+    default = tmp_path / "default"
+    project = tmp_path / "project"
+    default.mkdir()
+    project.mkdir()
+    sessions = SessionManager(tmp_path / "sessions")
+    controller = WebUIWorkspaceController(
+        session_manager=sessions,
+        default_workspace=default,
+        default_restrict_to_workspace=True,
+    )
+    explicit = default_workspace_scope(project, restrict_to_workspace=False)
+    controller.persist_scope("metadata-only", explicit)
+
+    def fail_full_read(_key: str) -> None:
+        raise AssertionError("scope lookup should not read full session history")
+
+    monkeypatch.setattr(sessions, "read_session_file", fail_full_read)
+
+    scope = controller.scope_for_session_key("websocket:metadata-only")
+
+    assert scope.project_path == project.resolve()
+    assert scope.access_mode == "full"