refactor: Decoupling chat architecture (#367)

* refactor: Migrate tests to Qt Creator plugin framework and update llmqore transports

* refactor: Move conversation history into IDE-free session library

* refactor: Extract turn context assembly behind injected ports

* build: Add RunQodeAssistTests target for the plugin test suite

* refactor: Route the chat through a Session and ChatBackend seam

sources/session/SessionEvent.cpp

@@ -0,0 +1,14 @@
+// Copyright (C) 2026 Petr Mironychev
+// SPDX-License-Identifier: GPL-3.0-or-later
+// Additional attribution terms under GPLv3 §7(b) apply — see LICENSE
+
+#include "session/SessionEvent.hpp"
+
+namespace QodeAssist::Session {
+
+QString turnIdOf(const SessionEvent &event)
+{
+    return std::visit([](const auto &alternative) { return alternative.turnId; }, event);
+}
+
+} // namespace QodeAssist::Session