#442 keyboard/joystick injection monitor commands

[Ingo Korb]

This patch adds two monitor commands that inject keyboard and joystick inputs directly into the matrix/port lines. This allows controlling software from the monitor interface that does not use the kernal input routines, unlike the existing keybuf command - pretty useful for automated tests. Both the text-based and the binary monitor are included.

If desired, I have an alternate version that uses cycles instead of frames for more precision and less user convenience. The frame count is relative to the emulated machine vsync, not the host.

AI Disclosure: This patch was vibed with Claude Opus 5.5 and received cursory manual review and testing, which resulted in no additional changes.

[gpz]

r46288 :)