appNameAllowed top-level property
Regex for allowed app name characters. \p{L}\p{M}\p{N} with Unicode — not \w (ASCII-only). Single space not \s — \s matches newlines.
Implementation
final RegExp appNameAllowed = RegExp(
r'^[\p{L}\p{M}\p{N}_ .&'
"'"
r'()+\-]+$',
unicode: true,
);