Cap claimed names at 20 chars to match the name authority

The nip05d authority now enforces a 3..=20 length; align the wallet's claim
validation (onboarding + settings) and the 'Names are 3-20 chars' hint across
all six locales so the wallet never offers a name the server will reject.

locales/de.yml

@@ -552,7 +552,7 @@ goblin:
     avail_available: "Verfügbar!"
     avail_taken: "Vergeben"
     avail_reserved: "Reserviert"
-    avail_invalid: "Namen haben 3–30 Zeichen: a–z, 0–9, _ oder -"
+    avail_invalid: "Namen haben 3–20 Zeichen: a–z, 0–9, _ oder -"
     avail_quarantined: "Nicht verfügbar"
     avail_unknown: "Prüfung fehlgeschlagen — Verbindungsproblem. Versuche es erneut."
   advanced:

locales/en.yml

@@ -552,7 +552,7 @@ goblin:
     avail_available: "Available!"
     avail_taken: "Taken"
     avail_reserved: "Reserved"
-    avail_invalid: "Names are 3–30 chars: a–z, 0–9, _ or -"
+    avail_invalid: "Names are 3–20 chars: a–z, 0–9, _ or -"
     avail_quarantined: "Not available"
     avail_unknown: "Couldn't check — connection hiccup. Try again."
   advanced:

locales/fr.yml

@@ -552,7 +552,7 @@ goblin:
     avail_available: "Disponible !"
     avail_taken: "Pris"
     avail_reserved: "Réservé"
-    avail_invalid: "Les noms font 3 à 30 caractères : a–z, 0–9, _ ou -"
+    avail_invalid: "Les noms font 3 à 20 caractères : a–z, 0–9, _ ou -"
     avail_quarantined: "Indisponible"
     avail_unknown: "Vérification impossible — souci de connexion. Réessayez."
   advanced:

locales/ru.yml

@@ -552,7 +552,7 @@ goblin:
     avail_available: "Доступно!"
     avail_taken: "Занято"
     avail_reserved: "Зарезервировано"
-    avail_invalid: "Имена 3–30 символов: a–z, 0–9, _ или -"
+    avail_invalid: "Имена 3–20 символов: a–z, 0–9, _ или -"
     avail_quarantined: "Недоступно"
     avail_unknown: "Не удалось проверить — сбой соединения. Попробуйте снова."
   advanced:

locales/tr.yml

@@ -552,7 +552,7 @@ goblin:
     avail_available: "Müsait!"
     avail_taken: "Alınmış"
     avail_reserved: "Ayrılmış"
-    avail_invalid: "Adlar 3–30 karakter: a–z, 0–9, _ ya da -"
+    avail_invalid: "Adlar 3–20 karakter: a–z, 0–9, _ ya da -"
     avail_quarantined: "Müsait değil"
     avail_unknown: "Kontrol edilemedi — bağlantı sorunu. Tekrar dene."
   advanced:

locales/zh-CN.yml

@@ -552,7 +552,7 @@ goblin:
     avail_available: "可用！"
     avail_taken: "已被占用"
     avail_reserved: "已保留"
-    avail_invalid: "用户名为 3–30 个字符：a–z、0–9、_ 或 -"
+    avail_invalid: "用户名为 3–20 个字符：a–z、0–9、_ 或 -"
     avail_quarantined: "不可用"
     avail_unknown: "无法检查 — 连接中断。请重试。"
   advanced:

src/gui/views/goblin/mod.rs

@@ -3781,7 +3781,7 @@ impl GoblinWalletView {
 				}
 				ui.add_space(10.0);
 				let name = claim.input.trim().trim_start_matches('@').to_lowercase();
-				let valid = name.len() >= 3 && name.len() <= 30;
+				let valid = name.len() >= 3 && name.len() <= 20;
 				if claim.checking {
 					ui.horizontal(|ui| {
 						View::small_loading_spinner(ui);

src/gui/views/goblin/onboarding.rs

@@ -842,7 +842,7 @@ impl OnboardingContent {
 				}
 				ui.add_space(10.0);
 				let name = self.claim.input.trim().to_lowercase();
-				let valid = name.len() >= 3 && name.len() <= 30;
+				let valid = name.len() >= 3 && name.len() <= 20;
 				if self.claim.checking {
 					ui.horizontal(|ui| {
 						View::small_loading_spinner(ui);