Release v0.5.0: isolate screenshot editor and support manifest-based updates

src/screenshot_launcher.cpp

@@ -0,0 +1,21 @@
+#include "app.h"
+
+namespace ks {
+void launchScreenshot(App &)
+{
+    auto path=std::filesystem::path(executable()).parent_path()/L"KSwitcher.Screenshot.exe";
+    if (!std::filesystem::exists(path))
+        throw std::runtime_error("KSwitcher.Screenshot.exe is missing. Extract the complete application package.");
+    auto command=L"\""+path.wstring()+L"\"";
+    STARTUPINFOW startup{sizeof(startup)};
+    PROCESS_INFORMATION process{};
+    // Grant foreground rights before the child's first selection window opens.
+    if (!CreateProcessW(path.c_str(),command.data(),nullptr,nullptr,FALSE,CREATE_SUSPENDED,
+                        nullptr,path.parent_path().c_str(),&startup,&process))
+        throw std::runtime_error(utf8(lastError(L"Cannot start screenshot editor")));
+    AllowSetForegroundWindow(process.dwProcessId);
+    ResumeThread(process.hThread);
+    CloseHandle(process.hThread);
+    CloseHandle(process.hProcess);
+}
+}