FA5's own single-class declarations lose the cascade to the later
.fa,.far,.fas family rule, so zibll-legacy values like "fa fab fa-weixin"
rendered with the Free font and came up blank — visible in the picker's
brand tab (500px…zhihu) and on every brand icon in the SPA and frontend
social links. Re-assert .fa.fab (and .fa.far weight) in the three
stylesheets that load FA5. Also remove the empty aksrt_svgs['qqww']
sprite entry, which surfaced as a blank built-in SVG item.
Assert the generated FA5 catalog, the REST route + sprite single
source, picker field wiring in widgets and nav menus, SVG-aware icon
sanitization on both save paths, the single aksrt-font-awesome handle
with FA5 class names, and the consolidated assets/icons layout.
kate522