upload: fix edge case for /index.html
tldr: the key mapper stripped /index.html, to ensure the entire segment was an index.html at the end and to avoid conflict
because the root of the site wasnt prefixed with a / before mapping, a path of index.html would just get mapped to path /index.html instead of /
fix: add special case for index.html
also make it a map bc more special cases may be added