Adding splitting screen and buffer switching

include/split_screen.h

@@ -0,0 +1,62 @@
+/**
+ * @file split_screen.h
+ * @brief Split screen management for displaying multiple buffers
+ */
+
+#ifndef SPLIT_SCREEN_H_
+#define SPLIT_SCREEN_H_
+
+#include "data.h"
+
+/**
+ * @brief Initializes split screen system
+ */
+void splitScreenInit(void);
+
+/**
+ * @brief Splits screen vertically (left-right)
+ * @param buffer_id_left Buffer ID for left pane
+ * @param buffer_id_right Buffer ID for right pane
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenVertical(int buffer_id_left, int buffer_id_right);
+
+/**
+ * @brief Splits screen horizontally (top-bottom)
+ * @param buffer_id_top Buffer ID for top pane
+ * @param buffer_id_bottom Buffer ID for bottom pane
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenHorizontal(int buffer_id_top, int buffer_id_bottom);
+
+/**
+ * @brief Returns to single buffer fullscreen
+ */
+void splitScreenUnify(void);
+
+/**
+ * @brief Switches active pane (focus moves between splits)
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenSwitchPane(void);
+
+/**
+ * @brief Updates the active pane's buffer
+ * @param buffer_id New buffer ID for active pane
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenSetPaneBuffer(int buffer_id);
+
+/**
+ * @brief Gets current screen layout
+ * @return Pointer to current ScreenLayout
+ */
+ScreenLayout *splitScreenGetLayout(void);
+
+/**
+ * @brief Gets active pane
+ * @return Pointer to active EditorPane
+ */
+EditorPane *splitScreenGetActivePane(void);
+
+#endif