Add Finder-style New Folder with inline rename on the Switch.

Create unique folders without a crashing prompt, then focus the name for editing; also fix folder association type and UTF-8 MTP string encoding.

src/ui/webroot/lang/nl.json

@@ -58,5 +58,9 @@
   "update.up_to_date_body": "OmniMTP {version} is de nieuwste release.",
   "update.check_failed_title": "Updatecontrole mislukt",
   "update.check_failed_body": "Kon de updateserver niet bereiken.",
-  "update.http_error": "Server gaf HTTP {code} terug."
+  "update.http_error": "Server gaf HTTP {code} terug.",
+  "btn.new_folder": "Nieuwe map",
+  "ctx.new_folder": "Nieuwe map",
+  "prompt.new_folder": "Mapnaam:",
+  "prompt.new_folder_default": "Nieuwe map"
 }