Every image and link pointed at docs/, which no longer exists - the README
rendered with six broken images. Repoints them at Documents/, updates the
board table to the real Schematics/Left|Right|Numpad tree, and renames
firmware/ to Firmware/ to match the capitalised convention.
Documents/README.md now describes the whole folder rather than just the
datasheets, since the diagrams and BOM live there too.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
