[desktop] Rework game list to use MVP architecture (#4042)

Closes #3480

moves the game list model/worker/private stuff to qt_common for later
use in QML

- `qt_common/game_list/model.{cpp,h}` is the model
- `yuzu/game/game_{grid,tree}.*` are the views
- `yuzu/game/game_list.cpp` is the presenter

This was done very lazily in a manner that "works" while largely
maintaining existing structure as much as possible. Most of it is
copy-paste, with some bonus reworks/cleanups thrown in.

Signed-off-by: crueter <crueter@eden-emu.dev>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4042
Reviewed-by: MaranBr <maranbr@eden-emu.dev>
Reviewed-by: Lizzie <lizzie@eden-emu.dev>

src/qt_common/game_list/model.h

@@ -0,0 +1,98 @@
+// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#pragma once
+
+#include <QFileSystemWatcher>
+#include <QStandardItemModel>
+#include <QStringList>
+#include <QVector>
+#include <memory>
+
+#include "common/common_types.h"
+#include "frontend_common/play_time_manager.h"
+#include "qt_common/config/uisettings.h"
+#include "yuzu/compatibility_list.h"
+
+namespace Core {
+class System;
+}
+
+class GameListDir;
+class GameListWorker;
+class QStandardItem;
+
+namespace FileSys {
+class ManualContentProvider;
+class VfsFilesystem;
+} // namespace FileSys
+
+class GameListModel : public QStandardItemModel {
+    Q_OBJECT
+
+public:
+    enum Column {
+        COLUMN_NAME,
+        COLUMN_FILE_TYPE,
+        COLUMN_SIZE,
+        COLUMN_PLAY_TIME,
+        COLUMN_ADD_ONS,
+        COLUMN_COMPATIBILITY,
+        COLUMN_COUNT,
+    };
+
+    explicit GameListModel(std::shared_ptr<FileSys::VfsFilesystem> vfs_,
+                           FileSys::ManualContentProvider* provider_,
+                           const PlayTime::PlayTimeManager& play_time_manager_,
+                           Core::System& system_, QObject* parent = nullptr);
+    ~GameListModel() override;
+
+    void AddDirEntry(GameListDir* entry_items);
+    void AddEntry(const QList<QStandardItem*>& entry_items, GameListDir* parent);
+    void DonePopulating(const QStringList& watch_list);
+
+    void PopulateAsync(QVector<UISettings::GameDir>& game_dirs);
+    void WorkerEvent();
+
+    bool IsEmpty() const;
+
+    void ToggleFavorite(u64 program_id);
+
+    void RefreshGameDirectory();
+    void RefreshExternalContent();
+    void ResetExternalWatcher();
+
+    void LoadCompatibilityList();
+
+    void OnUpdateThemedIcons();
+    void RetranslateUI();
+
+    QFileSystemWatcher* GetWatcher() const;
+
+    const CompatibilityList& GetCompatibilityList() const;
+
+    void SetFlat(bool flat);
+
+signals:
+    void ShowList(bool show);
+    void PopulatingCompleted(const QStringList& watch_list);
+    void SaveConfig();
+
+private:
+    friend class GameListWorker;
+
+    void AddFavorite(u64 program_id);
+    void RemoveFavorite(u64 program_id);
+
+    bool m_flat = false;
+
+    std::shared_ptr<FileSys::VfsFilesystem> vfs;
+    FileSys::ManualContentProvider* provider;
+    CompatibilityList compatibility_list;
+    const PlayTime::PlayTimeManager& play_time_manager;
+    Core::System& system;
+
+    std::unique_ptr<GameListWorker> current_worker;
+    QFileSystemWatcher* watcher = nullptr;
+    QFileSystemWatcher* external_watcher = nullptr;
+};