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/ContentBlock.hpp

@@ -0,0 +1,110 @@
+// 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 <QDebug>
+#include <QJsonObject>
+#include <QString>
+
+#include <variant>
+
+namespace QodeAssist::Session {
+
+struct TextBlock
+{
+    QString text;
+
+    bool operator==(const TextBlock &other) const = default;
+
+    friend QDebug operator<<(QDebug debug, const TextBlock &block)
+    {
+        return debug.nospace() << "Text(" << block.text << ")";
+    }
+};
+
+struct ThinkingBlock
+{
+    QString text;
+    QString signature;
+    bool redacted = false;
+
+    bool operator==(const ThinkingBlock &other) const = default;
+
+    friend QDebug operator<<(QDebug debug, const ThinkingBlock &block)
+    {
+        return debug.nospace() << "Thinking(" << block.text << ", sig=" << block.signature
+                               << ", redacted=" << block.redacted << ")";
+    }
+};
+
+struct ToolCallBlock
+{
+    QString id;
+    QString name;
+    QJsonObject arguments;
+    QString result;
+
+    bool operator==(const ToolCallBlock &other) const = default;
+
+    friend QDebug operator<<(QDebug debug, const ToolCallBlock &block)
+    {
+        return debug.nospace() << "ToolCall(" << block.id << ", " << block.name
+                               << ", args=" << block.arguments << ", result=" << block.result
+                               << ")";
+    }
+};
+
+struct AttachmentBlock
+{
+    QString fileName;
+    QString storedPath;
+
+    bool operator==(const AttachmentBlock &other) const = default;
+
+    friend QDebug operator<<(QDebug debug, const AttachmentBlock &block)
+    {
+        return debug.nospace() << "Attachment(" << block.fileName << ", " << block.storedPath
+                               << ")";
+    }
+};
+
+struct ImageBlock
+{
+    QString fileName;
+    QString storedPath;
+    QString mediaType;
+
+    bool operator==(const ImageBlock &other) const = default;
+
+    friend QDebug operator<<(QDebug debug, const ImageBlock &block)
+    {
+        return debug.nospace() << "Image(" << block.fileName << ", " << block.storedPath << ", "
+                               << block.mediaType << ")";
+    }
+};
+
+struct FileEditBlock
+{
+    QString id;
+    QString payload;
+
+    bool operator==(const FileEditBlock &other) const = default;
+
+    friend QDebug operator<<(QDebug debug, const FileEditBlock &block)
+    {
+        return debug.nospace() << "FileEdit(" << block.id << ", " << block.payload << ")";
+    }
+};
+
+using ContentBlock = std::
+    variant<TextBlock, ThinkingBlock, ToolCallBlock, AttachmentBlock, ImageBlock, FileEditBlock>;
+
+inline QDebug operator<<(QDebug debug, const ContentBlock &block)
+{
+    std::visit([&debug](const auto &alternative) { debug << alternative; }, block);
+    return debug;
+}
+
+} // namespace QodeAssist::Session