[refactor] reorganize platform and wire sources

apps/desktop/src/platform/window_drag.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <string>
+
+namespace crossdesk {
+
+// Starts the platform's native move loop for the window receiving the current
+// left-mouse-down event. Returns false when no suitable native event exists.
+bool StartNativeWindowDrag();
+
+// Hides the disabled native zoom button on CrossDesk's fixed-size main
+// window. Returns true once the matching AppKit window has been configured.
+bool HideDisabledMainWindowZoomButton();
+
+// Configures live resize and replaces the stream window's native Space
+// fullscreen action with an immediate, single-window fullscreen transition.
+// |slint_view| is the current stream window's AppKit NSView*. Passing the
+// identity explicitly prevents a closing window with the same title from
+// being selected during a later connection.
+bool ConfigureStreamWindowLiveResize(void* slint_view);
+
+// Drops the native stream-window reference if it belongs to |slint_view|.
+// This must run before the corresponding Slint component is destroyed.
+void UnregisterStreamWindow(void* slint_view);
+
+// Returns whether the configured stream window is currently the active AppKit
+// key window.
+bool IsStreamWindowActive();
+
+// Enters or leaves the stream window's animation-free fullscreen mode.
+bool SetStreamWindowFullscreen(bool fullscreen);
+bool IsStreamWindowFullscreen();
+
+// Opens an application-modal macOS file picker. The panel is made key before
+// entering its modal loop so it receives keyboard input immediately.
+std::string OpenNativeFileDialog(const std::string &title);
+
+} // namespace crossdesk