Initial rodecomp source snapshot

Source/Client/ApplicationWindow.h

@@ -0,0 +1,29 @@
+#ifndef RAGNAROK_SOURCE_CLIENT_APPLICATIONWINDOW_H
+#define RAGNAROK_SOURCE_CLIENT_APPLICATIONWINDOW_H
+
+#include <windows.h>
+
+namespace client {
+  // Recovered CreateWindowExA wrapper, not the full application initializer.
+  // Forces the title "Ragnarok 2026" and adds WS_SYSMENU to the caller's style.
+  HWND CreateApplicationWindow(
+    DWORD extendedStyle,
+    const char* className,
+    const char* ignoredTitle,
+    DWORD style,
+    int x,
+    int y,
+    int width,
+    int height,
+    HWND parent,
+    HMENU menu,
+    HINSTANCE instance,
+    void* parameter
+  );
+
+  // Original global main-window handle is borrowed; clips its client rectangle
+  // after converting both corners to screen coordinates. Returns ClipCursor.
+  BOOL ClipApplicationCursor(HWND window);
+}
+
+#endif