feat(nextcloud-files): Modul Dateien mit Nextcloud-Adresse, Verbindungsprüfung und gesicherter Verbindungsschicht

- Migration 20261008180000: NextcloudFilesConfig (Organisation) und NextcloudFilesAccount
  (Mandant UND Benutzer per Zeilenschutz, nur verschlüsseltes App-Passwort)
- Transportschicht ncRequest: feste Pfadanfänge, Segmentcodierung, keine Weiterleitungen,
  keine Cookies, Zeitgrenzen; Aufrufsperre pausiert den Ursprung nach jedem 429 und
  sperrt Zugangsschlüssel nach dem ersten 401
- Einstellungen: Adresse speichern/prüfen, Adresswechsel läuft alle Konten ab (mit Bestätigung)
- Controller mit Verwalten nur auf Einstellungen, Seed, Modul, Registrierung in Web
  (Ladefunktion, Symbol folder, Navigation, Layout) und Reiter Einstellungen
- RLS-Inventar fortgeschrieben, Testaufbau (tessera-nc-test) und E2E-Skripte

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

apps/web/src/messages/en.json

@@ -2320,5 +2320,53 @@
       "request": "The request failed. Please try again.",
       "loadStatus": "The state of the AutoDNS connection could not be loaded."
     }
+  },
+  "nextcloudFiles": {
+    "title": "Files",
+    "description": "View, upload, download and organise the files in your Nextcloud.",
+    "tabs": {
+      "files": "Files",
+      "settings": "Settings"
+    },
+    "notConfigured": {
+      "title": "Nextcloud has not been set up yet.",
+      "managerHint": "Enter the address of your Nextcloud in the settings.",
+      "userHint": "Please contact an administrator or someone with the Manage permission level.",
+      "goToSettings": "Go to settings"
+    },
+    "main": {
+      "server": "Nextcloud: {host}"
+    },
+    "errors": {
+      "request": "The request failed. Please try again.",
+      "loadStatus": "The state of the Nextcloud connection could not be loaded."
+    },
+    "settings": {
+      "save": "Save",
+      "saving": "Saving …",
+      "saved": "Saved.",
+      "address": {
+        "title": "Nextcloud address",
+        "description": "Enter the address the way your users open Nextcloud in the browser, for example https://cloud.your-company.com. Internal addresses are allowed.",
+        "label": "Address",
+        "placeholder": "https://cloud.your-company.com",
+        "test": "Check connection",
+        "testing": "Checking …",
+        "connectedUsers": "{count, plural, =0 {Nobody is connected right now.} one {One user is connected.} other {# users are connected.}}"
+      },
+      "reconnect": {
+        "message": "{count, plural, one {One user is connected. After the change they have to sign in again.} other {# users are connected. After the change everyone has to sign in again.}}",
+        "confirm": "Change address",
+        "cancel": "Cancel"
+      },
+      "hints": {
+        "title": "Notes for the Nextcloud administration",
+        "description": "So that signing in works reliably for everyone.",
+        "whitelist": "All Tessera users reach Nextcloud from the same address, that of the Tessera server. Several failed sign-ins make Nextcloud block this address for everyone. Add the address of the Tessera server to the allow list of the brute-force protection:",
+        "https": "Use https where possible. Certificates are verified; a private certificate authority has to be installed on the Tessera server.",
+        "trustedDomains": "The host name of the address has to be listed in the trusted domains (trusted_domains) of Nextcloud.",
+        "twoFactor": "Users with two-factor authentication connect through the browser; signing in with a password is not enough for them."
+      }
+    }
   }
 }