feat(kantine-datev): Kantinenabrechnung als Modul in neuer Gruppe Finanzbuchhaltung

- neue Seitenleisten-Kategorie accounting (Finanzbuchhaltung / Financial accounting)
- CSV (UTF-8, UTF-8 mit BOM, Windows-1252) pruefen, Vorschau mit Zeilenfehlern, DATEV-Lohn-ASCII-Export
- Beraternummer, Mandantennummer, Lohnart je Mandant als Admin-Einstellung (KantineDatevConfig mit Zeilenschutz), anfangs leer
- hochgeladene Daten werden nicht gespeichert; Download per Blob (auch im Desktop-Client)

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

apps/web/src/messages/en.json

@@ -1618,12 +1618,93 @@
       "loadError": "The custom modules could not be loaded."
     }
   },
+  "kantineDatev": {
+    "title": "Canteen billing",
+    "description": "Check canteen CSV files and download them as a DATEV payroll file for the salary run.",
+    "tabs": {
+      "billing": "Billing",
+      "settings": "Settings"
+    },
+    "loading": "Loading …",
+    "dropZone": {
+      "placeholder": "Drag a CSV file here or click",
+      "formats": ".csv, semicolon-separated, UTF-8 or Windows-1252",
+      "clear": "Remove file"
+    },
+    "noStorage": "The uploaded data is not stored.",
+    "checking": "Checking file …",
+    "notConfigured": {
+      "admin": "Consultant number, client number and wage type have not been set yet. Without them no DATEV file can be created.",
+      "adminAction": "Go to settings",
+      "user": "An administrator has to set the consultant number, client number and wage type first."
+    },
+    "summary": {
+      "title": "Check result",
+      "rows": "Rows",
+      "month": "Billing month",
+      "total": "Total amount",
+      "noMonth": "not detected"
+    },
+    "warnings": {
+      "title": "Notes",
+      "multipleMonths": "Different billing months detected: {months}. All rows should be in the same billing month."
+    },
+    "errors": {
+      "title": "Errors in the file",
+      "line": "Line",
+      "field": "Field",
+      "message": "Message",
+      "headerMissing": "The file has no header line.",
+      "headerColumns": "The header has too few columns. Is the separator correct (semicolon)?",
+      "columnCount": "The line has too few columns.",
+      "personalNrMissing": "Personnel number is missing",
+      "personalNrNotNumeric": "Personnel number must be numeric",
+      "betragMissing": "Amount is missing",
+      "betragFormat": "Amount must be in German number format (comma as decimal separator)",
+      "vonMissing": "Billing from is missing",
+      "vonFormat": "Billing from must be in the format DD.MM.YYYY",
+      "bisMissing": "Billing to is missing",
+      "bisFormat": "Billing to must be in the format DD.MM.YYYY",
+      "multiMonthRange": "The billing period spans several months",
+      "noRows": "The file contains no data rows.",
+      "settingsMissing": "Consultant number, client number and wage type have not been set yet.",
+      "hasErrors": "The file contains errors and cannot be exported.",
+      "qualityCheckFailed": "The generated file failed the quality check.",
+      "request": "The request failed. Please try again."
+    },
+    "fields": {
+      "header": "Header",
+      "zeile": "Line",
+      "datei": "File",
+      "personalNr": "Personnel number",
+      "betrag": "Amount",
+      "abrechnungVon": "Billing from",
+      "abrechnungBis": "Billing to",
+      "abrechnungVon/abrechnungBis": "Billing period"
+    },
+    "download": {
+      "button": "Download DATEV file",
+      "busy": "Creating file …",
+      "done": "The file {filename} has been downloaded."
+    },
+    "settings": {
+      "intro": "These values appear in the header and the lines of the DATEV file. They apply to all users of your tenant and only have to be set once.",
+      "beraterNr": "Consultant number",
+      "mandantNr": "Client number",
+      "lohnart": "Wage type",
+      "digitsOnly": "Please enter digits only (1 to 10 digits).",
+      "save": "Save",
+      "saving": "Saving …",
+      "saved": "The settings have been saved."
+    }
+  },
   "moduleCategories": {
     "domain-tools": "Domains",
     "security-tools": "Security",
     "fleet": "Fleet",
     "infrastructure": "Infrastructure",
     "procurement": "Procurement",
+    "accounting": "Financial accounting",
     "custom-modules": "Custom modules"
   }
 }