common : fix includes in arg.cpp and gemma3-cli.cpp (#12766)

* arg.cpp: add a missing include

* gemma3-cli.cpp: fix cinttypes include

common/arg.cpp

@@ -18,6 +18,7 @@
 #include <algorithm>
 #include <climits>
 #include <cstdarg>
+#include <filesystem>
 #include <fstream>
 #include <regex>
 #include <set>

examples/llava/gemma3-cli.cpp

@@ -10,7 +10,7 @@
 
 #include <vector>
 #include <limits.h>
-#include <inttypes.h>
+#include <cinttypes>
 
 #if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__))
 #include <signal.h>