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/TurnContextPorts.hpp

@@ -0,0 +1,53 @@
+// Copyright (C) 2026 Petr Mironychev
+// SPDX-License-Identifier: GPL-3.0-or-later
+// Additional attribution terms under GPLv3 §7(b) apply — see LICENSE
+
+#pragma once
+
+#include <QList>
+#include <QString>
+#include <QtGlobal>
+
+#include <optional>
+
+#include "session/TurnContext.hpp"
+
+namespace QodeAssist::Session {
+
+class IProjectContextPort
+{
+    Q_DISABLE_COPY_MOVE(IProjectContextPort)
+
+public:
+    IProjectContextPort() = default;
+    virtual ~IProjectContextPort() = default;
+
+    virtual ProjectInfo projectInfo() const = 0;
+    virtual QString projectRules() const = 0;
+};
+
+class ISkillsContextPort
+{
+    Q_DISABLE_COPY_MOVE(ISkillsContextPort)
+
+public:
+    ISkillsContextPort() = default;
+    virtual ~ISkillsContextPort() = default;
+
+    virtual QString alwaysOnBodies() const = 0;
+    virtual QString catalogText() const = 0;
+    virtual std::optional<InvokedSkill> findSkill(const QString &name) const = 0;
+};
+
+class ILinkedFilesPort
+{
+    Q_DISABLE_COPY_MOVE(ILinkedFilesPort)
+
+public:
+    ILinkedFilesPort() = default;
+    virtual ~ILinkedFilesPort() = default;
+
+    virtual QList<LinkedFile> readFiles(const QList<QString> &paths) const = 0;
+};
+
+} // namespace QodeAssist::Session