[FONTEXT] Implement paste operation (reactos#8615)

Support paste operation on Fonts folder.
JIRA issue: CORE-12861
- Add CFontBackgroundMenu.cpp and CFontBackgroundMenu.h
  to support background menu.
- Modify CFontExt::CreateViewObject and
  CFontExt::GetUIObjectOf methods.
- Re-implement foreground menu by using
  CDefFolderMenu_Create2 and CFontExt::MenuCallBack.
- Delete needless CFontMenu.cpp.
- Add IDS_PROPERTIES resource string.

Author: katahiromz

dll/shellext/fontext/CFontBackgroundMenu.cpp

@@ -0,0 +1,125 @@
+/*
+ * PROJECT:     ReactOS Font Shell Extension
+ * LICENSE:     GPL-2.0-or-later (https://spdx.org/licenses/GPL-2.0-or-later)
+ * PURPOSE:     Fonts folder shell extension background menu
+ * COPYRIGHT:   Copyright 2026 Katayama Hirofumi MZ <katayama.hirofumi.mz@gmail.com>
+ */
+
+#include "precomp.h"
+#include <shlwapi_undoc.h>
+
+WINE_DEFAULT_DEBUG_CHANNEL(fontext);
+
+CFontBackgroundMenu::CFontBackgroundMenu()
+{
+}
+
+CFontBackgroundMenu::~CFontBackgroundMenu()
+{
+}
+
+HRESULT WINAPI CFontBackgroundMenu::Initialize(CFontExt* pFontExt, const DEFCONTEXTMENU *pdcm)
+{
+    m_pFontExt = pFontExt;
+    m_psf = pdcm->psf;
+    m_pmcb = pdcm->pcmcb;
+    m_hwnd = pdcm->hwnd;
+    return S_OK;
+}
+
+// IContextMenu
+STDMETHODIMP CFontBackgroundMenu::QueryContextMenu(HMENU hMenu, UINT indexMenu, UINT idCmdFirst, UINT idCmdLast, UINT uFlags)
+{
+    TRACE("%d\n", idCmdFirst);
+    CString strProp(MAKEINTRESOURCEW(IDS_PROPERTIES));
+    INT idCmd = idCmdFirst;
+    AppendMenuW(hMenu, MF_STRING, idCmd++, strProp);
+    return MAKE_HRESULT(SEVERITY_SUCCESS, 0, idCmd - idCmdFirst);
+}
+
+STDMETHODIMP CFontBackgroundMenu::InvokeCommand(LPCMINVOKECOMMANDINFO lpcmi)
+{
+    INT idCmd = IS_INTRESOURCE(lpcmi->lpVerb) ? LOWORD(lpcmi->lpVerb) : -1;
+    TRACE("%d\n", idCmd);
+
+    if (idCmd == 0 || (idCmd == -1 && !lstrcmpiA(lpcmi->lpVerb, "properties")))
+    {
+        // Open "Fonts" properties
+        LPITEMIDLIST pidl = NULL;
+        HRESULT hr = SHGetSpecialFolderLocation(m_hwnd, CSIDL_FONTS, &pidl);
+        if (FAILED_UNEXPECTEDLY(hr) || !pidl)
+            return E_FAIL;
+
+        SHELLEXECUTEINFOW sei = {
+            sizeof(sei), SEE_MASK_INVOKEIDLIST | SEE_MASK_ASYNCOK, NULL, L"properties",
+            NULL, NULL, NULL, SW_SHOWNORMAL, NULL, const_cast<LPITEMIDLIST>(pidl)
+        };
+        BOOL bOK = ShellExecuteExW(&sei);
+        if (pidl)
+            CoTaskMemFree(pidl);
+        return bOK ? S_OK : E_FAIL;
+    }
+
+    if (idCmd == FCIDM_SHVIEW_INSERT || (idCmd == -1 && !lstrcmpiA(lpcmi->lpVerb, "paste")))
+    {
+        CComPtr<IDataObject> pDataObj;
+        HRESULT hr = OleGetClipboard(&pDataObj);
+        if (FAILED_UNEXPECTEDLY(hr) || !CheckDataObject(pDataObj))
+        {
+            // Show error message
+            CStringW text, title;
+            title.LoadStringW(IDS_REACTOS_FONTS_FOLDER);
+            text.LoadStringW(IDS_INSTALL_FAILED);
+            MessageBoxW(m_hwnd, text, title, MB_ICONERROR);
+            return E_FAIL;
+        }
+
+        return SHSimulateDrop(m_pFontExt, pDataObj, 0, NULL, NULL);
+    }
+
+    return S_OK;
+}
+
+STDMETHODIMP CFontBackgroundMenu::GetCommandString(UINT_PTR idCommand, UINT uFlags, UINT *lpReserved, LPSTR lpszName, UINT uMaxNameLen)
+{
+    TRACE("%d\n", idCommand);
+    if (idCommand == 0)
+    {
+        lstrcpynA(lpszName, "properties", uMaxNameLen);
+        return S_OK;
+    }
+    return E_FAIL;
+}
+
+// IContextMenu2
+STDMETHODIMP CFontBackgroundMenu::HandleMenuMsg(UINT uMsg, WPARAM wParam, LPARAM lParam)
+{
+    return HandleMenuMsg2(uMsg, wParam, lParam, NULL);
+}
+
+// IContextMenu3
+STDMETHODIMP CFontBackgroundMenu::HandleMenuMsg2(UINT uMsg, WPARAM wParam, LPARAM lParam, LRESULT *plResult)
+{
+    if (uMsg == WM_INITMENUPOPUP)
+    {
+        HMENU hMenu = (HMENU)wParam;
+        ::DeleteMenu(hMenu, FCIDM_SHVIEW_INSERTLINK, MF_BYCOMMAND);
+        return S_OK;
+    }
+    return E_NOTIMPL;
+}
+
+HRESULT
+APIENTRY
+CFontBackgroundMenu_Create(
+    CFontExt* pFontExt,
+    HWND hwnd,
+    IShellFolder* psf,
+    IContextMenu** ppcm)
+{
+    DEFCONTEXTMENU dcm;
+    ZeroMemory(&dcm, sizeof(dcm));
+    dcm.hwnd = hwnd;
+    dcm.psf = psf;
+    return ShellObjectCreatorInit<CFontBackgroundMenu>(pFontExt, &dcm, IID_PPV_ARG(IContextMenu, ppcm));
+}

dll/shellext/fontext/CFontBackgroundMenu.h

@@ -0,0 +1,41 @@
+/*
+ * PROJECT:     ReactOS Font Shell Extension
+ * LICENSE:     GPL-2.0-or-later (https://spdx.org/licenses/GPL-2.0-or-later)
+ * PURPOSE:     Fonts folder shell extension background menu
+ * COPYRIGHT:   Copyright 2026 Katayama Hirofumi MZ <katayama.hirofumi.mz@gmail.com>
+ */
+
+#pragma once
+
+class CFontBackgroundMenu
+    : public CComObjectRootEx<CComMultiThreadModelNoCS>
+    , public IContextMenu3
+{
+    HWND m_hwnd = nullptr;
+    CFontExt* m_pFontExt = nullptr;
+    CComPtr<IShellFolder> m_psf;
+    CComPtr<IContextMenuCB> m_pmcb;
+    LPFNDFMCALLBACK m_pfnmcb = nullptr;
+
+public:
+    CFontBackgroundMenu();
+    virtual ~CFontBackgroundMenu();
+    HRESULT WINAPI Initialize(CFontExt* pFontExt, const DEFCONTEXTMENU *pdcm);
+
+    // IContextMenu
+    STDMETHODIMP QueryContextMenu(HMENU hMenu, UINT indexMenu, UINT idCmdFirst, UINT idCmdLast, UINT uFlags) override;
+    STDMETHODIMP InvokeCommand(LPCMINVOKECOMMANDINFO lpcmi) override;
+    STDMETHODIMP GetCommandString(UINT_PTR idCommand, UINT uFlags, UINT *lpReserved, LPSTR lpszName, UINT uMaxNameLen) override;
+
+    // IContextMenu2
+    STDMETHODIMP HandleMenuMsg(UINT uMsg, WPARAM wParam, LPARAM lParam) override;
+
+    // IContextMenu3
+    STDMETHODIMP HandleMenuMsg2(UINT uMsg, WPARAM wParam, LPARAM lParam, LRESULT *plResult) override;
+
+    BEGIN_COM_MAP(CFontBackgroundMenu)
+        COM_INTERFACE_ENTRY_IID(IID_IContextMenu, IContextMenu)
+        COM_INTERFACE_ENTRY_IID(IID_IContextMenu2, IContextMenu2)
+        COM_INTERFACE_ENTRY_IID(IID_IContextMenu3, IContextMenu3)
+    END_COM_MAP()
+};