refactor(structure): normalize folder names with leading zeros for consistency

- Renamed all folders from format NEx (e.g., 1Ex, 2Ex...) to 0NEx (01Ex, 02Ex, etc.)
- Updated subdirectories and files accordingly
- Removed old main Makefile and tasks (a01.c–a09.c, solve.c, io_status.h), likely obsolete
- Cleaned up deprecated task binaries and configs

2025.02.28/4Ex/solve.c

@@ -1,20 +0,0 @@
-#include "solve.h"
-
-void t4_solve(char **a, int n, int (*cmp)(const char *, const char *))
-{
-	char *temp;
-	int i, j;
-	for (i=n; i > 0; --i)
-	{
-		for (j=0; j < i-1; ++j) 
-		{
-			if (cmp(a[j], a[j+1]) >= 0)
-			{
-				temp = a[j];
-				a[j] = a[j+1];
-				a[j+1] = temp;				
-			}
-		}
-	}
-}
-