fix(app): nothing secret is copied

The reading of the full reading's fixes found that copied recovery codes
and authenticator keys still reached clipboard histories (Windows, KDE's
Klipper, Gboard, Samsung's) and cloud clipboards, as no Flutter engine
marks a copy as sensitive, and that on Android an app in the background
can't empty the clipboard again, so the minute's clearing often never
happened.

As the developer decided: recovery codes are saved, like the phrase; an
authenticator's key is scanned as a QR code, opened in the authenticator
app, or typed from the screen. copySecret and its texts go.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

packages/halkyon_app/lib/l10n/halkyon_app_localizations_en.dart

@@ -302,12 +302,6 @@ class HalkyonAppLocalizationsEn extends HalkyonAppLocalizations {
   @override
   String get passwordDone => 'Done';
 
-  @override
-  String get passwordCopy => 'Copy';
-
-  @override
-  String get passwordCopied => 'Copied.';
-
   @override
   String get passwordSave => 'Save as a file';