The animated ZERO-wordmark boot splash showed for ~2s before the home; per the
request it's gone. Dropped the splash render branch + the m.booted flag/bootFrames
gating, and removed the now-dead RenderBoot + wordmark + newCanvasStyles (its last
users) and the --boot snapshot flag. The frame ticker stays (spinners); showSplash
stays (drives the empty state + placeholder). startup.go (default shell) untouched.
build/vet/test/windows/deadcode green.