Set the charset and the current language in the HTML head

<meta charset="utf-8"> keeps the encoding when a page is saved locally.
<html lang> now uses the language of the request instead of a fixed
"en", which matters for screen readers, hyphenation and the browser's
translation prompt.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

max/templates/base.html

@@ -1,7 +1,8 @@
 {% import "macros.html" as macros %}
 <!DOCTYPE html>
-<html lang="en">
+<html lang="{{ language }}">
 <head>
+    <meta charset="utf-8">
     <title>{{ webpagetitle }} &ndash; MAX</title>
     <meta name="viewport" content="width=device-width, initial-scale=1" />
     <meta name="robots" content="noindex" />

max/translations.py

@@ -19,7 +19,7 @@ class TranslationHandler:
     def init(cls, app):
         cls.app = app
         cls.always_reload_translations = app.debug
-        app.context_processor(lambda: dict(t=t))
+        app.context_processor(lambda: dict(t=t, language=cls.language))
 
     @classmethod
     def is_language_available(cls, language):