Nudge architecture diagram footer up to avoid dark-mode cropping (#16)

Moves the footer text from y=820 to y=795 in the 880-tall SVG canvas so it has ~85px of bottom padding instead of ~60px. Prevents some GitHub dark-mode renderers from clipping the descenders. PNG regenerated at 1100px.

Co-authored-by: Arun Sekhar <achand@microsoft.com>

Author: achandmsft