Add NightShot source

include/gif_recorder.hpp

@@ -0,0 +1,41 @@
+#pragma once
+
+#include "config.hpp"
+
+#include <windows.h>
+
+#include <string>
+
+namespace gif_recorder {
+
+struct Options {
+    int fps = 30;
+    int quality = 8;
+    // 0 means manual stop. hardLimitSeconds is always enforced.
+    int durationSeconds = 0;
+    int hardLimitSeconds = 30;
+    bool captureCursor = true;
+};
+
+struct StartRequest {
+    RECT screenRect{};
+    Options options{};
+    HWND notificationTarget = nullptr;
+};
+
+struct Result {
+    bool success = false;
+    std::wstring path;
+    std::wstring message;
+    int frameCount = 0;
+    int elapsedMilliseconds = 0;
+};
+
+[[nodiscard]] bool start(const StartRequest& request);
+void stop();
+[[nodiscard]] bool active();
+// Called by the main window after consuming WM_NIGHTSHOT_GIF_FINISHED.
+void releaseFinished();
+void shutdown();
+
+} // namespace gif_recorder