fix: Saldo-Abgleich erklaert die Abweichung verstaendlich

Die Meldung nannte nur Zahlen ("Laut Datei / errechnet / Differenz") und
sagte nicht, was zu tun ist. Sie beschreibt jetzt in Worten, was nicht
aufgeht und ab welcher Zeile beide auseinanderlaufen.

Dazu ein Hinweis auf die haeufigste Ursache, wenn kein Zeilenfilter
gesetzt ist: Revolut legt Giro, Erspartes und Anlagekonto in EINE Datei,
jedes mit eigener Kontostand-Spalte. Ohne Filter springt die Spalte
zwischen den Produkten und der Abgleich kann gar nicht aufgehen.

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

web/src/locales/en.json

@@ -347,9 +347,9 @@
     "skipCurrency": "other currency",
     "colBalance": "Balance (running)",
     "reconOk": "Balance check passes: all {{n}} steps match the file's balance column.",
-    "reconDiff": "Balance check failed. Per file: {{file}} · computed: {{app}} · difference: {{diff}}.",
-    "reconFirst": "First mismatch on {{date}} at “{{payee}}”: bank {{expected}}, detected {{actual}}.",
-    "reconOpening": "Opening balance per file: {{value}} (enter it on the account so the balance matches).",
+    "reconDiff": "The balance doesn't add up. The file ends at {{file}}, but the rows add up to {{app}} – {{diff}} missing or too much.",
+    "reconFirst": "They start to diverge on {{date}} at “{{payee}}”: the file's balance column moves by {{expected}}, while the row itself states {{actual}}.",
+    "reconOpening": "Before the first row the file stood at {{value}}. Enter that as the account's opening balance, dated the day before.",
     "needsTarget": "pick account",
     "filterColumn": "Only rows from column",
     "filterValue": "with value",
@@ -357,7 +357,8 @@
     "filterNone": "— no filter —",
     "filterHint": "Revolut puts every pocket (Current, Savings, Investments …) into ONE file, each with its own balance. Filter to one product here and create separate accounts for the others – otherwise pocket movements are counted twice.",
     "removeEntry": "Remove entry",
-    "removeEntryConfirm": "Remove the history entry “{{file}}”? Its transactions have already been undone."
+    "removeEntryConfirm": "Remove the history entry “{{file}}”? Its transactions have already been undone.",
+    "reconMixedHint": "Does the file hold several accounts or products? Revolut puts current, savings and investment into ONE file, each with its own balance column. The check only works once you set the row filter above (e.g. Product = Current) and import the other products separately."
   },
   "password": {
     "show": "Show password",