fix(web/app): stop the workspace from crashing on paginated lists

Three runtime problems showed up as soon as /app/@me was opened:

- /me/spaces now answers with a page object, but the shell still called find()
  on it; unwrap items at the query layer instead of every call site.
- /me/devices has the same shape and had the same latent bug.
- the workspace route declared path-only children, which React Router reports
  as leaf routes without an element; collapse it into one splat route, the
  shell already parses the pathname itself.

Also ship favicon.png: the manifest and the service worker reference it, and it
was missing from the public root.