VICE x64 is a GUI emulator that requires a real X11/Wayland display.
In this headless environment the KERNAL/BASIC/CHAR/1541 ROMs had to be
fetched manually, autostart produced blank screenshots (no display
to render to), and no other C64 emulator is installed. The oscar64
built-in emulator (-e) is the practical headless test tool. VICE is
left in build.sh as -v / -V for interactive use in a real terminal
session, but tasks.md and README.md are updated to reflect that the
development loop and all Verify steps use the oscar64 emulator.
Removed the failed test artifacts from src/build/.