Stale GL_UNPACK state in gl4es and a missing pre-release GPU sync
caused diagonal-banded corruption in the 3D view. Synthetic key
press/release must track the real controller button or touch down/up
edges, not fire together in one call - fixes a typed movement key
sticking forever, then a follow-up that had silently broken A-button
jump and on-screen keyboard arrow keys. Also adds force-rebuild.sh for
the known stageEngine stale-cache issue.
ml