Phase 2: MSIX 패키지 + IExplorerCommand 셸 익스텐션

C++ 셸 익스텐션 (src/EverythingToJpeg.Shell/)
- WRL RuntimeClass 패턴으로 IExplorerCommand 두 핸들러 구현
- Quick(빠른 변환) / Dialog(설정 창) verb를 다른 CLSID로 분리
- Invoke()에서 EverythingToJpeg.exe로 verb + 파일 경로 전달
- VS 2026 빌드 검증, /utf-8 한글 라벨 지원

MSIX 패키징 (packaging/)
- Package.appxmanifest: com:SurrogateServer + desktop4:FileExplorerContextMenus
- 26개 확장자 × 2 verb 자동 노출
- BuildMsix.ps1: dotnet publish + msbuild + makeappx 일관 파이프라인
- CreateDevCert.ps1 / Install-EverythingToJpeg.ps1: 자체 서명 인증서 워크플로
- GenerateAssets.ps1: placeholder 로고 자동 생성

CI/CD
- .github/workflows/release.yml: 태그 푸시 시 미서명 MSIX 자동 빌드 + 첨부

검증
- 50MB MSIX 산출 확인 (packaging/dist/EverythingToJpeg-x64.msix)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/EverythingToJpeg.Shell/dllmain.cpp

@@ -0,0 +1,188 @@
+// EverythingToJpeg shell extension — IExplorerCommand handlers
+// Two verbs:
+//   - QuickCommandHandler  → "EverythingToJpeg.exe quick "<paths>""
+//   - DialogCommandHandler → "EverythingToJpeg.exe dialog "<paths>""
+
+#include "pch.h"
+
+#pragma warning(disable : 4324)
+
+using Microsoft::WRL::ClassicCom;
+using Microsoft::WRL::ComPtr;
+using Microsoft::WRL::InhibitRoOriginateError;
+using Microsoft::WRL::Module;
+using Microsoft::WRL::ModuleType;
+using Microsoft::WRL::RuntimeClass;
+using Microsoft::WRL::RuntimeClassFlags;
+
+namespace {
+
+constexpr const wchar_t* kExeFileName = L"EverythingToJpeg.exe";
+
+std::wstring QuoteForCommandLineArg(const std::wstring& arg) {
+    const std::wstring quotable_chars(L" \\\"");
+    if (arg.find_first_of(quotable_chars) == std::wstring::npos) {
+        return arg;
+    }
+
+    std::wstring out;
+    out.push_back(L'"');
+    for (size_t i = 0; i < arg.size(); ++i) {
+        if (arg[i] == L'\\') {
+            const size_t start = i;
+            size_t end = start + 1;
+            for (; end < arg.size() && arg[end] == L'\\'; ++end) {}
+            size_t backslash_count = end - start;
+            if (end == arg.size() || arg[end] == L'"') {
+                backslash_count *= 2;
+            }
+            for (size_t j = 0; j < backslash_count; ++j)
+                out.push_back(L'\\');
+            i = end - 1;
+        }
+        else if (arg[i] == L'"') {
+            out.push_back(L'\\');
+            out.push_back(L'"');
+        }
+        else {
+            out.push_back(arg[i]);
+        }
+    }
+    out.push_back(L'"');
+    return out;
+}
+
+std::filesystem::path ResolveExePath() {
+    std::filesystem::path module_path{
+        wil::GetModuleFileNameW<std::wstring>(wil::GetModuleInstanceHandle()) };
+    module_path = module_path.remove_filename();
+    module_path /= kExeFileName;
+    return module_path;
+}
+
+HRESULT LaunchAppWithItems(const wchar_t* verb, IShellItemArray* items) {
+    if (!items) return S_OK;
+
+    DWORD count = 0;
+    RETURN_IF_FAILED(items->GetCount(&count));
+    if (count == 0) return S_OK;
+
+    auto exe_path = ResolveExePath();
+
+    auto command = wil::str_printf<std::wstring>(LR"-("%s" %s)-",
+        exe_path.c_str(), verb);
+
+    for (DWORD i = 0; i < count; ++i) {
+        ComPtr<IShellItem> item;
+        if (FAILED(items->GetItemAt(i, &item))) continue;
+
+        wil::unique_cotaskmem_string path;
+        if (FAILED(item->GetDisplayName(SIGDN_FILESYSPATH, &path))) continue;
+
+        command = wil::str_printf<std::wstring>(LR"-(%s %s)-",
+            command.c_str(),
+            QuoteForCommandLineArg(path.get()).c_str());
+    }
+
+    wil::unique_process_information process_info;
+    STARTUPINFOW startup_info = { sizeof(startup_info) };
+    RETURN_IF_WIN32_BOOL_FALSE(CreateProcessW(
+        nullptr,
+        command.data(),
+        nullptr,
+        nullptr,
+        FALSE,
+        CREATE_NO_WINDOW,
+        nullptr,
+        nullptr,
+        &startup_info,
+        &process_info));
+
+    return S_OK;
+}
+
+template <typename Derived>
+class CommandHandlerBase : public RuntimeClass<
+    RuntimeClassFlags<ClassicCom | InhibitRoOriginateError>,
+    IExplorerCommand>
+{
+public:
+    IFACEMETHODIMP GetTitle(IShellItemArray*, PWSTR* name) override {
+        return SHStrDupW(Derived::Title(), name);
+    }
+
+    IFACEMETHODIMP GetIcon(IShellItemArray*, PWSTR* icon) override {
+        auto exe = ResolveExePath();
+        return SHStrDupW(exe.c_str(), icon);
+    }
+
+    IFACEMETHODIMP GetToolTip(IShellItemArray*, PWSTR* infoTip) override {
+        *infoTip = nullptr;
+        return E_NOTIMPL;
+    }
+
+    IFACEMETHODIMP GetCanonicalName(GUID* guidCommandName) override {
+        *guidCommandName = GUID_NULL;
+        return S_OK;
+    }
+
+    IFACEMETHODIMP GetState(IShellItemArray*, BOOL, EXPCMDSTATE* cmdState) override {
+        *cmdState = ECS_ENABLED;
+        return S_OK;
+    }
+
+    IFACEMETHODIMP GetFlags(EXPCMDFLAGS* flags) override {
+        *flags = ECF_DEFAULT;
+        return S_OK;
+    }
+
+    IFACEMETHODIMP EnumSubCommands(IEnumExplorerCommand** enumCommands) override {
+        *enumCommands = nullptr;
+        return E_NOTIMPL;
+    }
+
+    IFACEMETHODIMP Invoke(IShellItemArray* items, IBindCtx*) override {
+        return LaunchAppWithItems(Derived::Verb(), items);
+    }
+};
+
+}  // namespace
+
+class __declspec(uuid("801B2DD3-632C-4731-9510-AEAE09345264"))
+    QuickCommandHandler final
+    : public CommandHandlerBase<QuickCommandHandler>
+{
+public:
+    static constexpr const wchar_t* Title() { return L"JPEG로 빠른 변환"; }
+    static constexpr const wchar_t* Verb() { return L"quick"; }
+};
+
+class __declspec(uuid("CEBA1DB7-9175-4DF6-A362-490DEA49B598"))
+    DialogCommandHandler final
+    : public CommandHandlerBase<DialogCommandHandler>
+{
+public:
+    static constexpr const wchar_t* Title() { return L"JPEG로 변환…"; }
+    static constexpr const wchar_t* Verb() { return L"dialog"; }
+};
+
+CoCreatableClass(QuickCommandHandler)
+CoCreatableClass(DialogCommandHandler)
+CoCreatableClassWrlCreatorMapInclude(QuickCommandHandler)
+CoCreatableClassWrlCreatorMapInclude(DialogCommandHandler)
+
+BOOL APIENTRY DllMain(HMODULE, DWORD, LPVOID) {
+    return TRUE;
+}
+
+_Check_return_
+STDAPI DllGetClassObject(REFCLSID rclsid, REFIID riid, LPVOID* ppv) {
+    if (ppv == nullptr) return E_POINTER;
+    *ppv = nullptr;
+    return Module<ModuleType::InProc>::GetModule().GetClassObject(rclsid, riid, ppv);
+}
+
+__control_entrypoint(DllExport)
+STDAPI DllCanUnloadNow(void) {
+    return Module<ModuleType::InProc>::GetModule().GetObjectCount() == 0 ? S_OK : S_FALSE;
+}