Bring the file manager, transfers, settings and games views in line with the
split HTTP APIs (dump jobs, copy/extract progress, DNS filter and system
status), refresh the styling and document the API, pkg install flow and
architecture, together with the repository issue and pull request templates.
Replace the embedded UI with a file manager: sidebar, details table, keyboard shortcuts, uploads, copy/move and extraction. Games, System, Transfers and Settings use the same components. The previous UI is archived in web/legacy/ and left out of the embedded resources.
The restyle is flat: donation banner, credits with the maintainer photo, and no gradients or card shadows. JavaScript stays ES5.