Add AIX platform-specific process_file() with filename capture

[uptycs-rmack]

According to the lsof FAQ it can't obtain path name components from the kernel name caches on AIX. At a minimum I can read the leaf node filename from the file struct so you get more than just the volume mount point and device file.

Changes:

• Added process_file() implementation to lib/dialects/aix/dfile.c
• Disabled USE_LIB_PROCESS_FILE in lib/dialects/aix/machine.h to use
  the dialect-specific implementation
• Filename capture for DTYPE_VNODE files by reading f_fnamep from the
  file structure when the vnode points to a regular file or directory
• Combine leaf filename with filesystem mount point for better context
• Use ellipsis (...) to indicate missing path components
• Add comprehensive documentation explaining AIX's name cache limitation

Example output:

• Before: "/var (/dev/hd9var)"
• After: "/var/.../error.log" (for /var/logs/app/error.log)

This provides the best possible path information given AIX's kernel
limitations, where no accessible name cache exists for full path
reconstruction.