Post-shader framebuffers (for shaders at output resolution, and those
that keep the previous frame) are sized for the output they were built
for. Moving the game to a TV or back, or the TV changing size, left them
sized for the other one. SetOutputOverride now asks for a rebuild when
the output changes.
Also corrects the design doc: "auto" render resolution follows the
device's screen, not the TV.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>