Ship Swedish (sv-SE) locale #27180

Is your feature request related to a problem?

Swedish is translated but not shipped. sv-SE is ~99% complete on Transifex, and the
catalogs are already on main (web/xliff/sv-SE.xlf, locale/sv_SE/), but locales.yaml
has ship: false for it, so it is neither built into the web UI nor offered in the
language picker. Swedish users therefore always see the login flow in English.

Swedish public sector organisations (municipalities, government agencies) generally
require end-user facing services to be available in Swedish, which currently rules out a
fully localised authentik login for them.

Describe the solution you'd like

Ship sv-SE: set ship: true in locales.yaml and run make gen-locales, as was done
for Bengali in #24788 (and is proposed for Danish in #26776). We're happy to open that PR.

Describe alternatives that you've considered

Replacing labels via brand custom CSS (::before/::after). This only changes the
visual text: screen readers still announce the English strings (WCAG 2.5.3 "Label in
Name"), placeholders and server-side error messages cannot be changed, and the CSS breaks
easily on upgrades. Building our own image with a Swedish locale works, but every
installation would have to maintain its own fork.

Additional context

We run authentik for a Swedish occupational health platform and can help review the
Swedish translation on Transifex, starting with the login and recovery flows.

Edit: the first version of this issue asked for Swedish to be added from scratch, based
on 2025.10.1. That was outdated: the translation already exists upstream, so the
attached files are no longer needed and have been removed.