add thumbhash use `github.com/galdor/go-thumbhash` and `github.com/evanw/thumbhash`
database:
add `thumbhash` column for `files` table
image:
add `EncodeThumbHash()` function use `go.n16f.net/thumbhash`
router:
add `/api/task/files/thumbhash` endpoint to check thumbhask
task:
add `CheckThumbHash()` function
web/scripts:
add thumbhash logic for `load_*` scripts
add `thumbhash.js` from `https://github.com/evanw/thumbhash/blob/main/js/thumbhash.js`, edited
web/styles/gallery:
add thumbhash transition when thumbnail loaded
adjust style for wrapped imgs
web/templates:
add `role="main"` for gallery and artwork id pages
render thumbhash script for gallery pages
Hubert Chen
2b8e238e72
