file-server: add Service-Worker-Allowed header
=/ mime-type=@t (rsh 3 (crip <p.u.data>))
:: Should maybe inspect to see how long cache should hold
::
- [[200 ['content-type' mime-type] max-1-da:gen ~] `q.u.data]
+ =/ headers
+ :~ content-type+mime-type
+ max-1-da:gen
+ 'Service-Worker-Allowed'^'/'
+ ==
+ [[200 headers] `q.u.data]
==
::
++ lowercase
