Initial CYD TF card info display with LVGL.

Mount microSD on VSPI and show type, format, and capacity on the CYD screen.

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

include/sd_info.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <Arduino.h>
+
+struct SdCardInfo {
+  bool mounted;
+  bool present;
+  const char *type;       // MMC / SDSC / SDHC / UNKNOWN / NONE
+  const char *filesystem; // FAT12 / FAT16 / FAT32 / exFAT / FAT / —
+  uint64_t card_bytes;    // 卡物理容量
+  uint64_t total_bytes;   // 分区总容量
+  uint64_t used_bytes;
+  uint64_t free_bytes;
+  uint32_t root_files;    // 根目录条目数
+  String error;           // 失败原因
+};
+
+bool sd_init();
+void sd_deinit();
+SdCardInfo sd_read_info();
+String format_bytes(uint64_t bytes);