fix: 修复启动白屏与地图崩溃问题

- SetUseOpenGL(false): QGLWidget 在当前系统不兼容，改用软件渲染
- ExtensionHost_v2: 添加 contributionRegistry() getter 修复空指针
- main.cpp: 两阶段启动 (show → QTimer::singleShot → initialize)
- mainwindow: 分离构造函数与 initialize()，结尾调用 onTabIndexChanged(3)
- 修复 Qt DLL 部署：使用 windeployqt 确保运行时库版本匹配

App/core/CommandRegistry.h

@@ -0,0 +1,41 @@
+#ifndef COMMANDREGISTRY_H
+#define COMMANDREGISTRY_H
+
+#include <QObject>
+#include <QMap>
+#include <QStringList>
+
+struct CommandEntry {
+    QString name;
+    QString description;
+    QString pluginName;
+    int commandId = 0;
+    bool enabled = true;
+};
+
+class CommandRegistry : public QObject
+{
+    Q_OBJECT
+public:
+    explicit CommandRegistry(QObject *parent = nullptr);
+
+    void registerCommand(const QString &name, const QString &description,
+                         const QString &pluginName, int commandId = 0);
+    void unregisterCommand(const QString &name);
+    void setCommandEnabled(const QString &name, bool enabled);
+
+    QStringList commandNames() const;
+    CommandEntry command(const QString &name) const;
+    bool hasCommand(const QString &name) const;
+    int commandCount() const;
+
+signals:
+    void commandRegistered(const QString &name);
+    void commandUnregistered(const QString &name);
+    void commandEnabledChanged(const QString &name, bool enabled);
+
+private:
+    QMap<QString, CommandEntry> m_commands;
+};
+
+#endif