fix(review): keep vendored scanners byte-identical; wide-safe XML sniff

Two review items applied maintainer-side to save a roundtrip:

1. Restore both vendored ObjectScript scanner.c files to the pristine
   upstream bytes (a formatter pass had rewritten indentation/braces).
   Vendored grammar files stay byte-for-byte upstream except for the
   include repoint documented in MANIFEST.md - style churn breaks
   upstream diffability on re-vendor.
2. The Studio Export XML sniff in detect_file_language used a raw
   fopen on a repository path; cbm_fopen keeps it working on
   non-ASCII Windows paths (project rule, same class as DeusData#996).

Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>

Author: DeusData