gbhub: control socket + gbtype to inject shell input without the OSK

Typing into a Game Boy meant driving the on-screen keyboard by hand. But
the link port already *is* the shell's console: bytes the hub sends
un-SLIP-framed land straight on stdin (that's what GB.type() has always
done for spawn-mode command scripting). This just exposes it.

gbhub now serves a control socket (/tmp/gbhub.ctl, world-connectable like
the join socket) accepting two commands: 'list' and 'type [idx]' followed
by a payload (delimited by the client's half-close). Injection is chunked
and paced to respect the 64-byte kernel console ring, so arbitrarily long
input - even multi-line scripts - reaches the shell without overflow. The
server runs in both daemon and spawn modes.

tools/gbtype is the client:
  tools/gbtype 'ls -l'        run a command on GB0 (Enter appended)
  tools/gbtype -g 1 ps        target the Nth joined Game Boy
  tools/gbtype -n abc         no trailing Enter
  tools/gbtype -r             just press Enter
  tools/gbtype -l             list connected Game Boys
  printf 'ls\nuname\n' | tools/gbtype    pipe a script via stdin

Options precede the command; the first non-option word starts literal
text, so 'gbtype ls -l' needs no quoting. No root required.

Verified end to end: injected list/uname/echo through the real CTL
protocol and saw the shell execute each and echo output back.

0 files changed, 0 insertions, 0 deletions