PHLEGM v8 checkpoint 23 — MACHINE TRACE GUI toggle

Windows and Linux graphical monitors now expose a full-width MACHINE TRACE: Off/On
button directly beneath the Tree / Icons, GUI Font, PPU Skip, and APU Skip rows.
Click to enable snapshots immediately and once every two seconds. Click again
to stop. Each snapshot goes to the console log and GUI history. CPU instruction
execution, PPU/APU enablement, and emulator timing remain unchanged by default.
The existing one-shot MACHINE TRACE console command remains available.

Native compilation and hands-on runtime testing must still be performed for the
Windows 32/64 and Linux x86/x86_64 backends.
