feat(i18n): complete Portuguese, add Brazilian Portuguese (pt_BR)

Fill the ~74 UI strings pt.i18n.json was missing (saved searches, label
scanning, Plantaré, lot history), then add pt_BR as a proper Brazilian
variant rather than a copy of European Portuguese: tu/teu/tua -> você/
seu/sua with matching verb conjugation, partilhar -> compartilhar, and
Guardar -> Salvar for UI actions (seed-saving keeps "guardar", the
correct term in both variants). Wires AppLocale.ptBr into the language
picker and regenerates slang output.

apps/app_seeds/lib/i18n/strings_en.g.dart

@@ -460,6 +460,9 @@ class Translations$settings$en {
 	/// en: 'Português'
 	String get langPt => 'Português';
 
+	/// en: 'Português (Brasil)'
+	String get langPtBr => 'Português (Brasil)';
+
 	/// en: 'Asturianu'
 	String get langAst => 'Asturianu';
 
@@ -2864,6 +2867,7 @@ extension on Translations {
 			'settings.langEs' => 'Español',
 			'settings.langEn' => 'English',
 			'settings.langPt' => 'Português',
+			'settings.langPtBr' => 'Português (Brasil)',
 			'settings.langAst' => 'Asturianu',
 			'settings.langFr' => 'Français',
 			'settings.langDe' => 'Deutsch',
@@ -3289,9 +3293,9 @@ extension on Translations {
 			'plantare.statusReturned' => 'Returned',
 			'plantare.statusForgiven' => 'Settled',
 			'plantare.openSection' => 'Open',
-			'plantare.settledSection' => 'Done',
 			_ => null,
 		} ?? switch (path) {
+			'plantare.settledSection' => 'Done',
 			'plantare.removeConfirm' => 'Remove this commitment?',
 			'plantare.returnBy' => ({required Object date}) => 'Return by ${date}',
 			'plantare.overdue' => 'overdue',