Fix #131: remove duplicate header and includes in ds_dispatch.c

[philphauler]

Summary

Remove the duplicate copyright header and #include block in ds_dispatch.c.

Problem

ds_dispatch.c contains two consecutive copyright headers and two sets of
#include directives. The first block (lines 1-38) is the current Draco
header with the correct includes for the dispatch module. The second block
(lines 40-78) is an older DS v2.6.1 header with includes from what was
previously ds_cmds.c, likely left behind during a refactor.

The duplicate #include <stdio.h> and duplicate #include "ds_msgids.h" etc.
are harmless to the compiler (include guards prevent double inclusion) but
are clearly unintended.

Fix

Delete the second block (39 lines). The first header and its includes are
preserved unchanged. Zero functional change.

Fixes #131.

[philphauler]

Pure cleanup — removes a duplicate #include block (39 lines, copy-paste artifact). No behavioral change.