fix(i18n+settings): rename pt-BR→pt, fix theme/locale persistence

Root cause: user_settings table was missing theme, locale, font_family,
font_size columns — PocketBase silently dropped them on every save.
Added the four columns via PocketBase API.

Also:
- listOne now sorts by -updated so the most-recent settings record wins
- PARAGLIDE_LOCALE cookie is now cleared when switching back to English
- pt-BR renamed to pt throughout (messages, inlang settings, validLocales)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ui/project.inlang/settings.json

@@ -1,7 +1,7 @@
 {
 	"$schema": "https://inlang.com/schema/project-settings",
 	"baseLocale": "en",
-	"locales": ["en", "ru", "id", "pt-BR", "fr"],
+	"locales": ["en", "ru", "id", "pt", "fr"],
 	"modules": [
 		"https://cdn.jsdelivr.net/npm/@inlang/plugin-message-format/dist/index.js"
 	],