fix: "Keine Konten" nennt jetzt die Ursache

Drei verschiedene Faelle sahen alle gleich aus: Die Bank schickte nichts, sie
schickte Eintraege ohne Kennung (die still verworfen wurden), oder alle Konten
waren schon bekannt – Letzteres meldete faelschlich "0 Konten", obwohl alles
in Ordnung war.

Die Antwort unterscheidet jetzt uebermittelt / neu / bekannt / ohne_kennung.
Die Rueckkehr-Seite zeigt bei null nutzbaren Konten den passenden Hinweis: Im
eingeschraenkten Betrieb gibt eine Bank nur heraus, was zuvor im Control Panel
unter "Activate by linking accounts" verknuepft wurde.

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

web/src/locales/en.json

@@ -587,7 +587,7 @@
     "connect": "Connect",
     "notMapped": "not mapped to an account yet",
     "mapHint": "Without a mapping nothing is fetched from this account.",
-    "noAccountsFound": "No accounts were returned.",
+    "noAccountsFound": "No accounts were returned. In restricted mode the bank only releases what you linked at Enable Banking under “Activate by linking accounts” – add this bank there and reconnect here.",
     "sync": "Fetch transactions",
     "synced": "{{geholt}} transactions checked · {{neu}} new in the inbox.",
     "noMapping": "No account mapped – map one above first, then it will fetch.",
@@ -620,6 +620,9 @@
     "failed": "That did not work",
     "failedHint": "The code from the bank is single-use and short-lived. Start the connection again in the settings.",
     "missing": "The bank did not return a code.",
-    "toSettings": "Go to settings"
+    "toSettings": "Go to settings",
+    "noAccounts": "Connected, but the bank returned no account",
+    "noAccountsHint": "In restricted mode the bank only releases accounts you linked at Enable Banking yourself. Open your application there, press “Activate by linking accounts” and pick this bank – then connect again here.",
+    "noAccountsDropped": "The bank sent {{n}} entries but without an identifier, so nothing can be fetched. That is one for Enable Banking support; send me the message and I will draft the question."
   }
 }