FTL诊断：L0探针窗口绑定路径日志（FAT读LPN→物理页+写目标）+重格式化行带fr码

Src/freertos.c

@@ -260,9 +260,13 @@ void StartDefaultTask(void *argument)
           } \
       } while (0)
       FRESULT hfr;
+      nand_ftl_set_tree_probe(1);
       FS_VOL_PROBE(hfr);
       if (hfr != FR_OK) {
           FS_VOL_PROBE(hfr);   /* 两击确认 */
+      }
+      nand_ftl_set_tree_probe(0);
+      if (hfr != FR_OK) {
           nand_ftl_scan_checks();   /* 诊断：环上 checkpoint 的 epoch 分布 */
       }
       if (hfr != FR_OK) {
@@ -270,7 +274,8 @@ void StartDefaultTask(void *argument)
               hfr == FR_INT_ERR || hfr == FR_DISK_ERR ||
               hfr == FR_NO_FILE || hfr == FR_NO_PATH ||
               hfr == FR_INVALID_NAME || hfr == FR_NO_FILESYSTEM) {
-              DBG_INFO("[FS] volume FAT invalid, reformatting...");
+              DBG_INFO("[FS] volume FAT invalid (fr=%d), reformatting...",
+                       (int)hfr);
               f_mount(NULL, "", 0);
               {
                   static uint8_t fs_work2[FF_MAX_SS];