fix: replace strtol with strtoll for 64-bit hex literal parsing on 32-bit platforms

The previous implementation used strtol() for parsing hex literals, which only supports up to 32-bit values on 32-bit architectures. This caused hex literals larger than 0x7FFFFFFF to overflow or fail. Changed to strtoll() which guarantees 64-bit parsing regardless of platform word size.

Also updated the error message to include the actual sizeof(long int) for debugging, uncommented the previously disabled 64-bit hex literal examples in syntax.wren, and added a test case for 0xdeadbeef to verify the fix works correctly.

example/syntax.wren

@@ -130,9 +130,8 @@ class Literals is SyntaxExample {
     1.0
     -12.34
     0x1000000
-// Literals larger than 0x1000000 are only valid in 64 bit builds
-//    0xdeadbeef
-//    0x1234567890ABCDEF
+    0xdeadbeef
+    0x1234567890ABCDEF
   }
 
   strings {