feat(i18n): add update flag strategy settings

Add new "updateFlags" section to settings navigation and implement update flag strategy configuration. The strategy allows users to choose when update badges appear:
- Match updates by base model (only show when new release shares same base model)
- Flag any available update (show whenever newer version exists)

Includes translations for English, German, Spanish, and French locales.

py/routes/handlers/misc_handlers.py

@@ -201,6 +201,7 @@ class SettingsHandler:
         "priority_tags",
         "model_card_footer_action",
         "model_name_display",
+        "update_flag_strategy",
     )
 
     _PROXY_KEYS = {"proxy_enabled", "proxy_host", "proxy_port", "proxy_username", "proxy_password", "proxy_type"}