Range-diff !502

back to !502 web: UX review small fixes

 -:  ------- >  1:  584dc8d web: one empty-state register — no CLI commands, no 'yet' on finished items
 -:  ------- >  2:  a8ca19c web: MR list offers a fork link or a sign-in prompt to visitors who cannot open one directly
 -:  ------- >  3:  ff759b5 web: search scope caption is permanent; document the tab zero-count rule
 -:  ------- >  4:  fcf2ea4 e2e: the unread list's empty state reads 'no unread notifications'
 1:  a07110a =  5:  f7a4bb9 web: new-issue form takes milestone and assignee, one dispatch
 2:  5c42977 =  6:  c0b5c73 web: watch button names all three states, muted included
 3:  a04d56f =  7:  508463c web: Discussion heading before the comment thread on issue and MR pages
 4:  ff19017 =  8:  4989dbf web: build page's Live note says the page updates itself
 5:  11b06ce =  9:  bf4c721 web: rail and phone More menu render New repository/Settings/Admin/Log out from one list
 -:  ------- > 10:  145dec1 e2e: the build page's live note reads 'This page updates itself'