Nyx: emuMMC Manage window, Tools UI, and misc updates

- Add gui_emu_tools: emuMMC Manage window with correct positioning (LV_PROTECT_PARENT + re-parent to win)
- Tools: single SD button (tap = SD partition manager, 3s hold = eMMC)
- Remove emuSD from Nyx UI (tabs, UMS, partition manager); keep bootloader emusd
- Shorten Create emuMMC description text by one character
- Storage/build/config and dependency updates

Co-authored-by: Cursor <cursoragent@cursor.com>

bdk/storage/file_based_storage.h

@@ -0,0 +1,15 @@
+#ifndef _FILE_BASED_STORAGE_H
+#define _FILE_BASED_STORAGE_H
+
+#include <bdk.h>
+
+
+int file_based_storage_init(const char *base_path);
+void file_based_storage_end();
+
+int file_based_storage_read(u32 sector, u32 num_sectors, void *buf);
+int file_based_storage_write(u32 sector, u32 num_sectors, void *buf);
+
+u32 file_based_storage_get_total_size();
+
+#endif