fix: "Marke" heisst jetzt Geraeteschluessel

"Geraetemarke" war ein ausgedachtes Wort, das nirgends erklaert wurde – man
las "Marke" und wusste nicht, was gemeint ist oder woher man sie bekommt.
Jetzt "Geraeteschluessel", mit einem Einleitungstext, der sagt was es ist
(ein langes Passwort nur fuers Telefon, nicht das Anmelde-Passwort), was es
darf und was beim Verlust zu tun ist.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

web/src/locales/en.json

@@ -470,12 +470,12 @@
   },
   "tokens": {
     "title": "Quick capture via shortcut",
-    "intro": "A device token lets an iOS shortcut send payments to Certain, so you can record what a purchase was for while you still remember. The token may only record: it cannot read bookings, change anything, or export.",
-    "name": "Device name",
+    "intro": "A device key is a long password for your phone only – not your login password. It lets an iOS shortcut send payments to Certain and nothing else: no reading bookings, no changes, no exports. If the phone is lost, revoke the key here.",
+    "name": "What is the key for?",
     "namePlaceholder": "e.g. iPhone",
     "defaultAccount": "Default account",
     "create": "Create token",
-    "onceOnly": "This token is shown only now. Copy it before you move on.",
+    "onceOnly": "This is your device key. It is shown only NOW – copy it into the shortcut. Certain does not store it in clear text and cannot show it again later.",
     "copy": "Copy",
     "copied": "Copied",
     "copyFailed": "Copying failed – but the text can be selected.",