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/ChatView/ChatController.hpp

@@ -0,0 +1,79 @@
+// Copyright (C) 2024-2026 Petr Mironychev
+// SPDX-License-Identifier: GPL-3.0-or-later
+// Additional attribution terms under GPLv3 §7(b) apply — see LICENSE
+
+#pragma once
+
+#include <QObject>
+#include <QString>
+
+#include "ChatModel.hpp"
+#include "session/Session.hpp"
+#include "templates/IPromptProvider.hpp"
+#include <context/ContextManager.hpp>
+
+namespace QodeAssist::Skills {
+class SkillsManager;
+}
+
+namespace QodeAssist::Chat {
+
+class ChatHistoryBridge;
+class LlmChatBackend;
+
+class ChatController : public QObject
+{
+    Q_OBJECT
+
+public:
+    explicit ChatController(
+        ChatModel *chatModel, Templates::IPromptProvider *promptProvider, QObject *parent = nullptr);
+
+    void setSkillsManager(Skills::SkillsManager *skillsManager);
+
+    void sendMessage(
+        const QString &message,
+        const QList<QString> &attachments = {},
+        const QList<QString> &linkedFiles = {},
+        bool useTools = false,
+        bool useThinking = false);
+    void clearMessages();
+    void cancelRequest();
+    void resetToRow(int rowIndex);
+
+    Session::Session *session() const;
+    Context::ContextManager *contextManager() const;
+
+    void setChatFilePath(const QString &filePath);
+    QString chatFilePath() const;
+
+signals:
+    void errorOccurred(const QString &error);
+    void messageReceivedCompletely();
+    void requestStarted(const QString &requestId);
+    void messageUsageReceived(
+        int promptTokens, int completionTokens, int cachedPromptTokens, int reasoningTokens);
+
+private:
+    QList<Session::ContentBlock> composeUserBlocks(
+        const QString &message, const QList<QString> &attachments);
+    std::optional<Session::TurnContext> buildTurnContext(
+        const QString &message, const QList<QString> &linkedFiles) const;
+    void recordFileEditStatus(
+        const QString &editId, const QString &status, const QString &fallbackMessage);
+    void registerHistoricalEdits();
+
+    bool isImageFile(const QString &filePath) const;
+    QString getMediaTypeForImage(const QString &filePath) const;
+    QString encodeImageToBase64(const QString &filePath) const;
+
+    Templates::IPromptProvider *m_promptProvider = nullptr;
+    ChatModel *m_chatModel = nullptr;
+    Context::ContextManager *m_contextManager = nullptr;
+    Skills::SkillsManager *m_skillsManager = nullptr;
+    Session::Session *m_session = nullptr;
+    LlmChatBackend *m_backend = nullptr;
+    QString m_chatFilePath;
+};
+
+} // namespace QodeAssist::Chat