Beta 4a of Flujo is up. Started the debts and shared expenses feature,
plus two settings that were requested on my other projects.

First, a theme toggle. The app now supports a dark mode alongside the
default cream paper look. The toggle is in a small settings panel in the
header. The dark palette uses a warm dark brown instead of the usual
cold gray, so it still feels like the editorial aesthetic.

Second, multi-language support. The interface can switch between
Spanish and English. Switching reloads the page so all the static text
gets re-translated. The dynamic content (expenses, descriptions) stays
in whatever language the user typed it in.

Third, the structure for the debts tab is in place. A new “deudas” tab
appears next to resumen, apuntes and tickets. The HTML is there
(persons form, shared expense form with split method selector,
movements list, settle-up section, patterns section) but the JavaScript
logic comes in Beta 4b. The shared expense form supports four split
methods: equal, by shares (e.g. 2:1:1), exact amounts per person, and
by percentage. The settle-up section will use a greedy algorithm to
minimize the number of transfers needed to clear all debts.