fix(css): drop only flexslider.css, keep its JS

Surgical follow-up to the previous revert. The home-carousel indicator
dots drift because flexslider.css adds `.carousel li { margin-right: 5px }`
which bleeds into Bootstrap's carousel-indicators li. Bootstrap's
.active override removes margin on the active dot, but the inactive
keeps that 5px right margin — so when the inactive sits on the left
(slide 2 active), it pushes the active dot ~4px to the right.

The previous attempt also removed jquery.flexslider-min.js, which
empirically broke the hero/team carousels (the JS load seems to
participate in Bootstrap's data-ride auto-init timing on this custom
build). Keep the JS, drop only the CSS link plus the static file. Also
remove the now-superseded stage tweak at the bottom of praxis.css.

templates/partials/head.html

@@ -19,5 +19,4 @@
 <link rel="stylesheet" href="/css/bootstrap.min.css">
 <link rel="stylesheet" href="/fonts/font-awesome/css/font-awesome.min.css">
 <link rel="stylesheet" href="/css/mobile-menu.css">
-<link rel="stylesheet" href="/css/flexslider.css">
 <link rel="stylesheet" href="/css/praxis.css">